Crosslinkable polymeric compounds

ABSTRACT

The invention relates to organic polymers which can be crosslinked under the action of light and which are suitable for carrying out photomechanical processes. These polymers are photochemically considerably more sensitive than known comparable polymers and their sensitivity can additionally also be further increased by means of a combination with sensitizers. The molecular weight is at least 1,000. The polymers contain, as light-sensitive groups, groups of the formula I ##STR1## wherein R and R 1  independently of one another denote alkyl groups with at most 4 C atoms, or R and R 1  conjointly denote the remaining part of a 5-membered to 6-membered carbocyclic ring.

This is a Divisional of application Ser. No. 695,347, filed on June 14,1976, now U.S. Pat. No. 4,079,041, issued on Mar. 14, 1978.

The invention relates to new organic polymers which can be crosslinkedunder the action of electromagnetic waves. Since, in respect of theirphysical and chemical properties, the constituents, of the polymers,which are crosslinked under the action of electromagnetic radiation donot differ substantially from the constituents, of the polymers, whichare not affected by the radiation, photomechanical processes can becarried out using the new polymers.

A number of polymers which can be crosslinked under the action of lightare already known. In most of these light-sensitive polymers, thephoto-active groups are linked as side substituents to the polymerchain. In this connection there may be mentioned, in particular, thefollowing Japanese Published Specification: JA 49-128,991, JA49-128,992, JA 49-128,993, JA 50-5,376, JA 50-5,377, JA 50-5,378, JA50-5,379 and JA 50-5,380.

In these Japanese patent applications, processes for the manufacture oflight-sensitive polymers are claimed and these polymers contain, aslight-sensitive groups, groups of the formula II ##STR2## in which Rdenotes an aromatic radical and R' denotes H, halogen, alkyl or -CN.

However, known polymers of this type have the disadvantage that theirphotochemical sensitivity is much too low for particular phototechnicalapplications. This characteristic has an adverse effect in particular inthat, ultimately, images or relief images which are not sharp resultwhen corresponding photomechanical processes are carried out and thatthe exposure times required are too long.

In the case of these polymers it is also not possible to eliminate thisdisadvantage by using sensitisers for photochemical reactions.Apparently this is because the development of the action of thesesensitisers is very greatly diminished by these known light-sensitivepolymers.

The object of the invention is to provide polymers which can becrosslinked by light and which do not have the disadvantages of theknown polymers described, that is to say which have a greatersensitivity towards electromagnetic waves, and in which, in addition,this sensitivity can also be further considerably increased by means ofa combination with sensitisers.

The invention relates to polymers which can be crosslinked under theaction of electromagnetic waves, have an average molecular weight of atleast 1,000 and contain, per molecule, on average more than twomaleimide groups of the formula I ##STR3## wherein R₁ and R₂independently of one another denote alkyl groups with at most 4 carbonatoms, or R₁ and R₂ conjointly denote the remaining part of afive-membered to six-membered carbocyclic ring.

In particular, the polymers according to the invention contain thefollowing maleimide groups of the formula I: ##STR4##

Those polymers which contain the first mentioned of the three maleimidegroups are a particularly preferred form.

The polymers according to the invention are, in particular, polymericcompounds of the group comprising polyesters, polyester-amides,polyamides, polyimides, polyamideimides, polyester-amide-imides,polyethers, polyamines (including polyimines), polyurethanes,polycondensates based on phenol-formaldehyde (novolacs),polysaccharides, gelatine, organopolysiloxanes and polymers which areformed by homopolymerisation or copolymerisation of monomers containingreactive C═C double bonds.

Polymers according to the invention are, in particular, the following 7types (A to G) of polymeric compounds:

(A) Homopolymers or copolymers of monomers which contain reactive C═Cdouble bonds and have average molecular weights of between 1,000 and1,000,000 and which contain the maleimide groups of the formula I inmolecular chain members of the formulae ##STR5## in which MI denotes themaleimide group of the formula I and Y₂ denotes an aliphatic orcycloaliphatic or carbocyclicaromatic or araliphatic orheterocyclic-aliphatic or heterocyclic-aromatic radical (containing, ineach case, a total of at most up to 18 C atoms), and in which Y₁ has thesame definition as Y₂ or represents the grouping ##STR6## Y₃ has thesame definition as Y₂ or represents the grouping ##STR7## Y₄ has thesame definition as Y₂ or represents the grouping ##STR8## Y₅ has thesame definition as Y₂ or represents the grouping

    --CO--Y.sub.2 --

y₆ has the same definition as Y₂ and preferably denotes an aliphatic orcarbocyclic-aromatic radical and Y₇ has the same definition as Y₂ and qis preferably O, and in which R₃ denotes H or alkyl with 1 to 6 C atoms,R₄ denotes H or alkyl, preferably methyl, R₅, R₆ and R₇ independently ofone another denote H, halogen, cyano, alkyl, aryl or aralkyl, butpreferably H and R₈ denotes H, --COOH or --COO(CH₂)_(z) CH₃ (z= 0 to18).

(The following is to be stated, in principle, with regard to thechemical formulae in this patent application: if divalent molecularradicals which are characterized by a symbol (for example "Y") and whichrepresent parts of a basic formula are explained in more detail byfurther formulae, these divalent radicals are always spatially soindicated that they can be incorporated into the basic formula withoutrotation. The right-left arrangements of both the basic formula and ofthe formula of the particular divalent molecular radical explained inmore detail are thus to be left unchanged).

When (A) concerns copolymers, these preferably contain, in addition tothe molecular chain members carrying the maleimide groups, thosemolecular chain members which are derived from the following comonomers,which are free from maleimide groups: olefines, vinyl halides, forexample vinyl bromide, vinyl chloride and vinyl fluoride, vinylidenes,for example vinylidene chloride, nitriles of α,β-unsaturated acids, forexample acrylonitrile or methacrylonitrile, α,β-unsaturated acids andtheir esters or halogen derivatives, for example acrylic acid,methacrylic acid, crotonic acid, maleic acid, methyl methacrylate, ethylacrylate, propyl acrylate, butyl acrylate, octyl acrylate, 2-ethyl-hexylacrylate, ethyl methacrylate, isopropyl methacrylate, dimethylaminoethylmethacrylate, diethylaminoethyl acrylate, glycidyl methacrylate,glycidyl acrylate or chloromethyl methacrylate, α,β-unsaturatedcarboxylic acid amides and their derivatives, for example acrylamide andmethacrylamide, aromatic vinyl compounds, for example styrene,methylstyrene, vinyltoluene or α-chlorostyrene, vinyl ketones, forexample methyl vinyl ketone, vinyl esters, for example vinyl acetate,heterocyclic vinyl compounds, for example vinylpyridine andvinylpyrrolidone, vinyl ethers and compounds which have olefinic doublebonds.

(B) Polyamides or polyamide-imides which have average molecular weightsof between 1,000 and 50,000 and which contain the maleimide groups ofthe formula I in molecular chain members of the formulae ##STR9## inwhich MI represents the maleimide group of the formula I and Y₈represents an aliphatic radical with at least 2 C atoms or acycloaliphatic or araliphatic or carbocyclicaromatic orheterocyclic-aromatic radical (with, in each case, at most up to 18 Catoms), or represents a radical of the formula ##STR10## in which R₁₁denotes --CH₂ --, ##STR11## --SO₂ --, --S-- or --O--, and, in the caseof the polyamides, the radical --NH--Y₈ --NH-- can also represent thegrouping ##STR12## in which R₉ and R₁₀ independently of one another canbe H, methyl or phenyl.

(B) also includes copolyamides and copolyamide-imides which alsocontain, in addition to the molecular chain members carrying themaleimide groups, those molecular chain members which are derived fromcomonomers which are free from maleimide groups, that is to say fromdicarboxylic acids or from tri- and tetra-carboxylic acids and/ordiamines which are capable of forming imides.

Examples of such carboxylic acids or their derivatives are: succinicacid, succinic anhydride, glutaric acid, adipic acid, suberic acid,sebacic acid and dodecanedicarboxylic acid,1,3-cyclopentane-dicarboxylic acid, phthalic anhydride,hexahydroisophthalic acid, hexahydroterephthalic acid, terephthalicacid, isophthalic acid, 4,4'-dicarboxydiphenylethane,naphthalene-2,5-dicarboxylic acid, thiophene-2,5-dicarboxylic acid andpyridine-2,3-dicarboxylic acid as well as the corresponding dichlorides,diesters according to the definition and salts; trimellitic acid1,2-anhydride-chloride (1,3-dioxo-benzo[c] oxalane-5-carboxylic acidchloride), trimellitic anhydride and the Na or ammonium salt, and estersaccording to the definition, of trimellitic acid; pyromelliticdianhydride, 3,3',4,4'-benzophenone-tetracarboxylic acid dianhydride,2,3,3',4'-benzophenone-tetracarboxylic acid dianhydride,2,2',3,3'-benzophenonetetracarboxylic acid dianhydride,3,3',4,4'-diphenyl-tetracarboxylic acid dianhydride,bis-(2,3-dicarboxyphenyl)-methane dianhydride,bis-(2,5,6-trifluoro-3,4-dicarboxyphenyl)-methane dianhydride,2,2-bis-(2,3-dicarboxyphenyl)-propane dianhydride,bis-(3,4-dicarboxyphenyl) ether dianhydride,bis-(3,4-dicarboxyphenyl)-sulphone dianhydride,N,N-(3,4-dicarboxyphenyl)-N-methylamine dianhydride,bis-(3,4-dicarboxyphenyl)-diethylsilane dianhydride and 2,3,5,7- and1,2,5,6-naphthalene-tetracarboxylic acid dianhydride.

Examples which may be mentioned of diamines which are suitable forpolycondensation are: o-, m- and p-phenylenediamine, diaminotoluenes,such as 2,4-diaminotoluene, 1,4-diamino-2-methoxybenzene,2,5-diaminoxylene, 1,3-diamino-4-chlorobenzene,4,4'-diamino-diphenylmethane, 4,4'-diaminodiphenyl ether,4,4'-diaminodiphenyl thioether, 4,4'-diaminodiphenylsulphone,2,2'-diaminobenzophenone, 4,4'-diaminodiphenylurea, 1,8- or1,5-diaminonaphthalene, 2,6-diaminopyridine, 2,4-diaminopyrimidine,2,4-diamino-s-triazine, di-, tri-, tetra-, hexa-, hepta-, octa- anddeca-methylenediamine, 2,2-dimethylpropylenediamine,2,5-dimethylhexamethylenediamine, 4,4-dimethylheptamethylenediamine,3-methylheptamethylenediamine, 3-methoxyhexamethyldiamine,2,11-diaminododecane, 1,2-bis-(3-aminopropoxy)-ethane,N,N'-dimethylethylenediamine, N,N'-dimethyl-1,6-diaminohexane and thediamines of the formulae H₂ N(CH₂)₃ O(CH₂)₂ O(CH₂)₃ NH₂ and H₂ N(CH₂)₃S(CH₂)₃ NH₂ and 1,4-diaminocyclohexane,1,4-bis-(2-methyl-4-aminopentyl)-benzene and1,4-bis-(aminomethyl)-benzene.

(C) Polyesters which have average molecular weights of between 1,000 and50,000 and which contain the maleimide groups of the formula I inmolecular chain members of the formula ##STR13## in which MI denotes themaleimide group of the formula I and Y_(j9) denotes an aliphatic radicalwith at least 2 C atoms or a cycloaliphatic or araliphatic orcarbocyclic-aromatic or heterocyclic-aromatic or heterocyclic-aliphaticradical (with, in each case, a total of at most 18

atoms).

(C) also includes copolyesters which also contain, in addition to themolecular chain members carrying the maleimide groups, those molecularchain members which are derived from comonomers which are free frommaleimide groups, that is to say from dicarboxylic acids or fromdicarboxylic acid derivatives and/or diols which are capable ofundergoing a condensation reaction.

Examples of such carboxylic acids, or their derivatives, are: succinicacid, succinic anhydride, glutaric acid, adipic acid, suberic acid,sebacic acid and dodecanedicarboxylic acid,1,3-cyclopentane-dicarboxylic acid, phthalic anhydride,hexahydroisophthalic acid, hexahydroterephthalic acid, terephthalicacid, isophthalic acid, 4,4'-dicarboxydiphenylethane,naphthalene-2,5-dicarboxylic acid, thiophene-2,5-dicarboxylic acid andpyridine-2,3-dicarboxylic acid as well as the corresponding dichlorides,diesters according to the definition and salts; maleic acid and fumaricacid and their derivatives, trimellitic acid s1,2-anhydride-chloride(1,3-dioxo-benzo[c]oxalane-5-carboxylic acid chloride), trimelliticanhydride and the Na or ammonium salt, and esters according to thedefinition, of trimellitic acid; 2,3,3',4'-benzophenone-tetracarboxylicacid dianhydride, 2,2',3,3'-benzophenone-tetracarboxylic aciddianhydride, 3,3',4,4'-diphenyl-tetracarboxylic acid dianhydride,bis-(2,3-dicarboxyphenyl)-methane dianhydride,bis-(2,5-6-trifluoro-3,4-dicarboxyphenyl)-methane dianhydride,2,2-bis-(2,3-dicarboxyphenyl)-propane dianhydride,bis-(3,4-dicarboxyphenyl)-ether dianhydride,bis-(3,4-dicarboxyphenyl)-sulphone dianhydride,N,N-(3,4-dicarboxyphenyl)-N-methylamino dianhydride,bis-(3,4-dicarboxyphenyl)-diethylsilane dianhydride and 2,3,5,7- and1,2,5,6-naphthalene-tetracarboxylic acid dianhydride.

Examples which may be mentioned of diols which are suitable for acondensation reaction are: ethylene glycol, propylene glycol,1,3-propanediol, 1,4- and 2,3-butanediol, 2,2-dimethyl-1,3-propanediol(neopentylglycol), 1,5- and 2,4-pentanediol, 1,6- and 2,5-hexanediol,1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol,2-ethyl-2-butyl-1,3-propanediol, diethylene glycol, dipropylene glycol,1,2-, 1,3- and 1,4-cyclohexanediol, 1,4-bis-(hydroxymethyl)-cyclohexane,4-amino-cyclohexanol, 1,2-, 1,3- and 1,4-dihydroxybenzene,1,2-dihydroxy-3-methoxybenzene, 1,2-dihydroxy-4-nitrobenzene,2,6-dihydroxytoluene, 1,3-, 1,4-, 1,5- and 1,6-dihydroxynaphthalene,2,2'-dihydroxybiphenyl, 4,4'-dihydroxy-biphenyl,4,4'-dihydroxy-diphenylylmethane, 2,2'-bis-(4-hydroxyphenyl)-propane(bisphenol A), 2,2'- and 4,4'-dihydroxy-diphenlyl ether, 3,3'- and4,4'-dihydroxy-diphenylylsulphone, 2,4-dihydroxy-5-methyl-pyrimidine,2,3-dihydroxypyridine and 3,6-dihydroxy-pyridazine.

(D) Polymers of the type comprising polyesters which have averagemolecular weights of at least 1,000, which have been formed by reactionsof monomers containing epoxide groups with monomers containing carboxylgroups or anhydride groups and which contain the maleimide groups of theformula I in molecular chain members of the formulae ##STR14## in whichMI denotes the maleimide group of the formula I, Q₁ and Q₂ independentlyof one another denote --NR₁₆ -- or --O-- and R₁₆ represents hydrogen,alkyl with 1-4 carbon atoms or phenyl, and R₁₂, Y₁₀ and Y₁₁independently of one another denote an aliphatic or cycloaliphatic orcarbocyclic-aromatic or heterocyclic-aromatic or heterocyclic-aliphaticradical (with, in each case, a total of at most 18 C atoms) and R₁₃ hasthe same definition as R₁₂ or represents one of the groupings ##STR15##and in which, in the case of the first mentioned formula, the molecularradical --Q₁ --R₁₂ --Q₂ -- can also denote a group of the formulae##STR16##

(D) also includes copolyesters which also contain, in addition to themolecular chain members carrying the maleimide groups, those molecularchain members which are derived from comonomers which are free frommaleimide groups, that is to say from monomers which have, for example,two glycidyl groups, dicarboxylic acids and anhydrides or dianhydrides.

(E) Polycondensates based on phenol-formaldehyde (novolacs) which haveaverage molecular weights of at least 1,000 and which contain themaleimide groups of the formula I in molecular chain members of theformula ##STR17## in which MI represents the maleimide group of theformula I and Y₁₂ represents an aliphatic or cycloaliphatic orcarbocyclic-aromatic or heterocyclic-aliphatic or heterocyclicaromaticradical (with, in each case, a total of at most 18 C atoms), Z denotesone of the groupings --S--, ##STR18## --NR₁₆ -- or --O-- and R₁₆represents hydrogen, alkyl with 1-4 C atoms or phenyl.

(E) also includes those novolacs in which free glycidyl groups and/orfree OH groups are also present, in addition to the molecular chainmembers carrying the maleimide groups, such as, for example, novolacscorresponding to the following formula: ##STR19##

After irradiation, such condensates, which have some free epoxidegroups, can optionally be post-cured by means of epoxide curing agentswhich are active under hot conditions, in particular catalytic curingagents, such as dicyandiamide. The products post-cured in this waydisplay a higher ability for resisting heat than those crosslinked byirradiation only.

(F) Polyethyleneimines which have average molecular weights of between1,000 and 1,000,000 and which contain the maleimide groups of theformula I in molecular chain members of the formulae ##STR20## in whichMI denotes the maleimide group of the formula I and Y₁₃ denotes analiphatic or cycloaliphatic or carbocyclicaromatic orheterocyclic-aliphatic or heterocyclic-aromatic radical (with, in eachcase, a total of at most 18 C atoms).

(G) Polymers based on a polyether (especially phenoxy resins) which haveaverage molecular weights of 1,000 to 1,000,000 and which contain themaleimide groups of the formula I in molecular chain members of theformula ##STR21## in which MI denotes the maleimide group of the formulaI and Y₃ denotes an aliphatic or cycloaliphatic or carbocyclicaromaticor araliphatic or heterocyclic-aliphatic or heterocyclic-aromaticradical (containing, in each case, a total of at most up to 18 C atoms)or denotes the grouping ##STR22## and R₈ represents --H, --COOH or --COO(CH₂)_(z) CH₃ (z=0 to 18).

The polymers according to the invention can be manufactured according tomethods of synthesis which are in themselves known for the manufactureof macromolecules which have photoactive side groups (which are alsotermed pendant or hanging groups). In principle, the following routescan be used:

1. Incorporation of the light-sensitive group into an existing polymerchain and

2. Synthesis of the polymer chain from monomers which already containthe light-sensitive maleimide groups, it being possible to synthesisethe polymer chain by 2.1. polymerisation or 2.2. a polyaddition reactionor 2.3. a polycondensation reaction. It should be noted that the sameproducts can be obtained with methods 1 and 2, so that in many cases itis possible to use method 1 or method 2, as desired.

If the light-sensitive maleimide groups are incorporated by means of asecondary reaction into a polymer chain which already exists, thisincorporation is effected either by means of a condensation reaction,with the elimination of H₂ O, H₂ S, a hydrogen halide or the like, or bymeans of an addition reaction with simultaneous opening of a ringsystem, such as, for example, of a dicarboxylic acid anhydride group orof an epoxide group.

In the case of a condensation reaction, either the polymer contains sidegroups of the type --OH, --SH, --NH₂, alkyl-NH--, aryl--NH-- or thelike, and the compound which contains the maleimide group and is to becondensed with the polymer contains groups of the type --CO·Cl, --CO·OHor the like, or the conditions at the start are reversed, that is to saythe starting polymers contain side groups of the type --CO·Cl, --CO·OHor the like, and the compound which contains the maleimide group and isto be condensed with the polymer contains the partner groups suitablefor the condensation reaction, that is to say --OH, SH and the like. Thecondensation reaction is carried out according to known methods,preferably in solution.

When the maleimide group is incorporated into the polymer by means of anaddition reaction either the starting polymer contains, as a chainmember or as a side group, the dicarboxylic acid anhydride group orepoxide group suitable for the addition reaction and the compound whichcontains the maleimide group and is to be added onto the polymercontains the group suitable for opening the particular ring, such as,for example, --OH, --NH₂ and the like, or the conditions are reversed,that is to say the compound which contains the maleimide group and is tobe added onto the polymer contains the dicarboxylic acid anhydride groupor epoxide group and the starting polymer contains the group suitablefor opening the ring, that is to say --OH, --NH₂ and the like. Theseaddition reactions are also carried out according to known processes,such as are described in large numbers in the literature.

The products which follow may be listed as starting polymers which aresuitable for introducing the light-sensitive maleimide groups of theformula I by a condensation or addition reaction: polyacrylic acid,polymethacrylic acid, copolymers of these acids and other ethylenicallyunsaturated monomers, copolymers synthesised from maleic anhydride andethylenically unsaturated monomers such as methyl vinyl ether, ethylene,styrene, hexene-1, decene-1, tetracene-1 and octadecene---1, polymerswhich have isocyanate and isothiocyanate groups, polymers which havefree hydroxyl groups, such as monomers or copolymers of acrylic acidhydroxyalkyl esters and methacrylic acid hydroxyalkyl esters, polyvinylalcohols, natural or regenerated cellulose, cellulose derivatives,hydroxyalkylcellulose, polyethers based on the phenoxy resins,phenol-formaldehyde polycondensates (novolacs), polymers which have freeglycidyl groups, such as copolymers based on acrylic acid glycidylesters and methacrylic acid glycidyl esters, polyimines and polymerswhich have free amino groups, such as, for example, poly-p-aminostyrene.

Examples of solvents which can be used in the condensation and additionreactions described are N-methylpyrrolidone, dimethylformamide,dimethylacetamide, cyclohexanone, ethyl methyl ketone, isopropyl methylketone, γ-butyrolactone, pyridine, tetrahydrofurane, dioxane,tetramethylurea, hexametapol and sulpholane. The modified polymers canbe precipitated by adding a small amount of a slightly polar solvent.Examples of slightly polar solvents are diethyl ether, isopropanol,hexane, cyclohexane, benzene, toluene and chlorobenzene. This generallyadvantageous method on the one hand leads to readily soluble polymersand on the other hand permits clean separation of the polymers from thelow-molecular constituent of the reaction mixture.

Catalysts which promote the desired linking can be added to the reactionsolution. Thus, for example, the addition of tertiary amines,p-toluenesulphonic acid, sulphuric acid or Lewis acids is advantageousfor the formation of esters.

When the polymers according to the invention are manufactured bysynthesis from monomers which already contain the light-sensitivemaleimide groups of the formula I and optionally from additionalcomonomers which are free from maleimide groups, very specific reactionconditions must be observed depending on the nature of the particularpolymerisation, polyaddition reaction or polycondensation reaction.These reaction conditions and in particular data on the quantity ratios,temperatures, catalysts, accelerators, solvents and the like are alsodescribed in detail in the literature.

More precisely, the following should also be mentioned in detail in thisconnection: Re 2.1. (polymerisation)

In the case of known systems, the homopolymerisation orcopolymerisation, by free radical polymerisation, of monomers whichcontain more than one reactive C═C double bond leads to crosslinkedproducts. It is true that it is possible so to polymerise suitablemonomers, such as, for example, vinyl ether derivatives of cinnamicacid, by cationic mechanisms that only one C═C double bond isincorporated into the polymer, as has been described by Kato andHasegawa (Polymer Letters 8 [1970]). However, carrying out the reactionin this way is very involved and therefore technologically noteconomical. It has now been found that monomers which also contain, inaddition to the double bond present in the maleimide radical of theformula I, a further ethylenically unsaturated double bond which can bepolymerised more easily than the maleimide group of the formula I,surprisingly polymerise, by means of free radical initiators, forexample by means of organic peroxides, such as dilauroyl peroxide,didecanoyl peroxide, dibenzoyl peroxide or dicumyl peroxide, organicperoxycarbonates, such as dicyclohexyl peroxydicarbonate anddi-sec.-butyl peroxydicarbonate, di-tert.-butyl perbenzoate, inorganicper-compounds, such as hydrogen peroxide, potassium persulphate andammonium persulphate, or azo compounds, such as azoisobutyronitrile orazo-bis-( 2,4-dimethylvaleronitrile) or with the aid of redox systems,such as, for example, Fe²⁺ /H₂ O₂, in such a way that polymers areobtained which do not have a crosslinked structure and which contain thelight-active imidyl groups as side substituents which, according to theinvention, can subsequently be crosslinked by electromagnetic waves.

A further subject of the invention is thus also a process for themanufacture of the homopolymers and copolymers characterised under (A),which process is characterised in that a monomer which on the one handcontains a maleimide radical of the formula I and on the other handcontains a group which differs from the ethylenically unsaturated grouppresent in this maleimide radical but which is also ethylenicallyunsaturated and which can be polymerised more easily than the maleimidegroup of the formula I, is polymerised, optionally together with otherethylenically unsaturated compounds which can be copolymerised, by meansof free radical initiators. This process is preferably carried out "insolution". In principle, however, a polymerisation in bulk or inheterogeneous phase, such as emulsion polymerisation, suspensionpolymerisation or precipitation polymerisation, using the initiatorsdescribed is also possible. This polymerisation process is also carriedout by conventional methods.

According to the invention, the compounds employed as the monomers whichon the one hand contain a maleimide radical of the formula I and on theother hand contain a group which differs from the ethylenicallyunsaturated group present in this maleimide radical but which is alsoethylenically unsaturated are, preferably, those compounds whichcontain, as the last-mentioned group, a group from the series ##STR23##in which R denotes an alkyl group with at most 4 C atoms and M denotesoxygen or one of the radicals --O·CO--, --NH·CO-- or --CO·NH·CO--.

The maleimide monomers to be used according to the process of theinvention can be either homopolymerised or copolymerised. Examples ofsuitable comonomers are α-olefines, such as ethylene, propylene andisobutylene, vinyl compounds, such as vinyl chloride, vinylidenechloride, vinyl acetate, vinylpyridine, vinylpyrrolidone, styrene,methylstyrene, vinyl ketones, vinyl ethers, vinylimidazoles,vinylcarbazoles and vinylsulphonic acids, allyl compounds, acrylic andmethacrylic compounds, such as acrylic acid and the esters thereof ormethacrylic acid and the esters thereof, acrylamide, acrylonitrile,methacrylamide and methacrylonitrile, dicarboxylic acids and the estersthereof, such as fumaric acid or maleic acid, maleic anhydride andmaleimides, and also, in some cases, dienes, such as butadiene,chlorobutadiene, isoprene or chloroprene.

If the polymerisation is carried out in solution, solvents which can beused are inter alia, depending on the nature of the monomers used, thosewhich follow: water, toluene, benzene, tetrahydrofurane, ethyl acetate,ethylglycol and derivatives thereof, dioxane, acetone,dimethylformamide, dimethylacetamide and halogenated hydrocarbons ormixtures of such solvents. Depending on the choice of the solvent and ofthe reaction temperature, the initiators used will be the free-radicalinitiators mentioned or redox systems, in concentrations of 0.01 to 5percent by weight, preferably of 0.1-2.5 percent by weight, based on themonomer concentration.

Depending on the choice of the solvent and of the initiator, thereaction temperature is between 0 and 150° C., preferably between 20°and 120° C. When the reaction has ended, the polymer can be isolatedeither by distilling off the solvent or by precipitation in a solvent inwhich the polymer is insoluble. Depending on the concentration of theinitiator and on the reaction temperature, the average molecular weightof polymers manufactured in this way is 1,000 to 2,000,000; a molecularweight of 10,000 to 50,000 is preferably chosen. The molecular weightcan optionally be influenced by the addition of regulators, such asmercaptans, for example dodecylmercaptan, or allyl derivatives, forexample allyl alcohol. Re 2.3. (polycondensation reaction)

In order to manufacture products according to the invention by means ofa polycondensation reaction it is possible, for example, to usecompounds which contain a maleimide radical of the formula I and which,together with corresponding compounds which do not contain the maleimideradical, are able to form polycondensates. Polycondensation of compoundswhich contain at least two carboxylic acid groups, or of reactivederivatives of such dicarboxylic and polycarboxylic acids, withcompounds which contain at least two groups which are able to react withthe optionally functionally modified carboxylic acid groups, inparticular dihydroxy compounds (including diepoxy compounds) and diaminocompounds, hydroxyamino compounds and also monoepoxides and carboxylicacid anhydrides is preferred. At least one of the components in thecondensation reaction contains a maleimide group of the formula I. Ingeneral it is appropriate if, in addition to the component containingthe maleimide radical, a corresponding component which does not containthis radical is also co-condensed. The presence of the maleimide radicalin the carboxylic acid component is particularly preferred.

Examples which may be mentioned of such polycondensed compounds whichcontain the radical of the formula I are:5-dimethylmaleimidylbenzene-1,2,4-tricarboxylic acid (obtainable fromaminotrimellitic acid and dimethylmaleic anhydride),5-dimethylmaleimidylbenzene-1,2-(dicarboxylic acidanhydride)-4-carboxylic acid chloride (conversion of the tricarboxylicacid into the 1,2-dicarboxylic acid anhydride and reaction of the latterwith thionyl chloride), 5-dimethylmaleimidylbenzene-1,2-(dicarboxylicacid anhydride)-4-carboxylic acid ethyl ester (from the acid chloride),5-dimethylmaleimidylbenzene-1,3-dicarboxylic acid dichloride andN-glycidyl-dimethylmaleimide.

An acid chloride, esters, anhydride-chlorides or dianhydrides and, inthe case of diepoxy compounds, also dicarboxylic acids and, in the caseof monoepoxides, carboxylic acid anhydrides are preferably employed forthe polycondensation reactions.

In other respects the polycondensation reaction can be carried out in amanner which is in itself known, for example in a solvent attemperatures of -20° C. to +30° C. Examples of solvents which can beused are: aromatic hydrocarbons, such as benzene, toluene and xylenes;optionally halogenated aliphatic hydrocarbons, such as pentane,n-hexane, methylene chloride, chloroform and dichloromethane; aliphaticand cycloaliphatic ketones, such as acetone, methyl ethyl ketone,cyclopentanone and cyclohexanone; cyclic ethers, such astetrahydrofurane, tetrahydropyrane and dioxane; cyclic amides, such asN-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone andN-methyl-ε-caprolactam; N,N-dialkylamides of aliphatic monocarboxylicacids which have 1-3 carbon atoms in the acid part, such asN,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide andN,N-dimethyl-methoxyacetamide; alkyl esters of aliphatic monocarboxylicacids which contain a total of 2 to 6 carbon atoms, such as formic acidmethyl, ethyl and n-butyl esters or acetic acid methyl, ethyl andn-butyl esters; hexamethylphosphoric acid triamide (hexametapol);N,N,N',N'-tetramethylurea, tetrahydrothiophene dioxide (sulpholane) anddialkylsulphoxides, such as dimethylsulphoxide and diethylsulphoxide.

The polycondensation reactions can also be carried out in the melt inthe presence of customary polycondensation catalysts at temperatures ofabout 150° to 280° C.

Catalysts which can be used are, for example, antimony compounds, suchas antimony triacetate or antimony trioxide, zinc acetate, calciumacetate, germanium compounds or alkali metal salts of organic carboxylicacids.

The polymers according to the invention are suitable for various uses,but in particular for crosslinking under the action of electromagneticwaves.

Crosslinking leads to insoluble prodcuts and makes it possible toproduce relief images by image-wise exposure and subsequent developing,that is to say dissolving out the proportion of the polymer which wasnot exposed and therefore not crosslinked.

In this application it is important that the sensitivity of the polymersto light can be quite considerably incresed by sensitisation, and thisrepresents a particularly great advance compared with polymers of thestate of the art.

Suitable sensitisers are, in particular, triplet sensitisers, the use ofwhich effects crosslinking by means of triplet energy transfer from theexcited sensitiser to the maleimide radical of the formula I which isnot excited; in this context compare N. J. Turro, "Mol. Photochemistry",W. A. Benjamin Inc. [1965], page 107. The two conditions for effectivesensitisation are as follows:

1. The triplet sensitiser must display an absorption maximum whichpermits a light absorption, in the range of more than 300 nm, which isadequate for practical purposes and 2. The triplet energy transfer mustbe exothermic.

It has been found that the polymers containing the maleimide radical ofthe formula I have a T₁ state which lies between 50 and 53kilogram-calories per mol and therefore, from the start, all the tripletsensitisers which permit exothermic energy transfer in the rangementioned, that is to say which have a T₁ state of at least 50 kcal/mol.are suitable for sensitising. For example, the following sensitisers canbe used. (The figures give the particular triplet energies in kcal/mol).

    ______________________________________                                        Benzene      85    Carbazole           70                                     Phenol       82    Triphenylamine      70                                     Benzoic acid 78    Hexachlorobenzene   70                                     Benzonitrile 77    4,4-Diphenylcyclohexadienone                                                                      69                                     Aniline      77    1,2-Dibenzoylbenzene                                                                              69                                     Xanthone     74    Thiophene           69                                     Acetophenone 74    Benzophenone        69                                     Diisopropyl ketone                                                                         74    1,4-Diacetylbenzene 68                                     Diphenyl sulphide                                                                          74    Fluorene            68                                     Diphenylamine                                                                              72    Triphenylene        67                                     Benzaldehyde 72    4-Cyanobenzophenone 66                                     Diphenylselenium                                                                           72    Diphenyl            65                                     Thioxanthone (also Acridine yellow     58                                     halogen-substituted)                                                                       65                                                                                  1-Naphthyl phenyl ketone                                                                          57                                     Phenylglyoxal                                                                              63                                                                                  Chrysene            57                                     Anthraquinone                                                                              62                                                                                  1-Acetonaphthol     56                                     Quinoline    62                                                                                  1-Naphthaldehyde    56                                     Phenanthrene 62                                                                                  Diacetyl            55                                     Flavone      62                                                                                  Coronene            55                                     Michler's ketone                                                                           61                                                                                  Benzil              54                                     Naphthalene  61                                                                                  Fluorenone          53                                     4-Acetyldiphenyl                                                                           61                                                                                  Fluorescein (acid)  51                                     Nitrobenzene 60                                                                                  p-Nitrostilbene     50 -2-Acetonaphthene 59                ______________________________________                                    

The following should also be mentioned

    ______________________________________                                        Anthrone     72       5-Nitroacenaphthene                                                                           56.6                                    Benzanthrone 72       4-Nitroaniline  55                                      2-Nitrofluorene                                                                            59       Naphthothiazoline                                                                             55                                      Quinoxaline and sub-  1-Acetylamino-4-nitro-                                  stitution products                                                                         55 to 59 naphthalene     52.5                                    4-Nitrodiphenyl                                                                            58                                                               ______________________________________                                    

The triplet yield, and thus the sensitivity, can be increased byintroducing elements which have a high atomic weight, for example iodineor bromine.

The possibilities for use of the polymers according to the inventionlie, for example, in the field of photoproduction processes, themanufacture of printing plates and photographic processes which do notuse silver compounds. In the case of photographic processes which do notuse silver compounds, the polymer image which is barely to poorlyvisable can, after exposure and developing, be rendered readily visibleby staining with oil-soluble dyestuffs or, when the polymer containsacid groups such as carboxylic acid groups or sulphonic acid groups, bystaining with cationic dyestuffs. In the present case also, thelight-active layers can be applied to suitable carrier materials by thecustomary techniques, such as spray coating, whirler coating,cascadecasting coating and curtain coating.

EXAMPLES

Several instructions for manufacturing the compounds which are to beused according to the examples and which contain the maleimide groups ofthe formula I (both monomers which can be processed to polymers andsubstances for the modification of already existing polymers) aredescribed in the text which follows.

(a) N-(4-Hydroxycyclohexyl)-dimethylmaleimide

126 g (1 mol) of dimethylmaleic anhydride and 115 g (1 mol) of4-aminocyclohexanol are warmed, in an oil bath whilst stirring, to 120°to 125° C. (internal temperature) for 30 minutes. After cooling to 20°C., the reaction product is dissolved in 500 ml of methylene chlorideand extracted once with 100 ml of 1 N NaOH, whilst cooling with ice. Thereaction product is then washed twice with water and dried over sodiumsulphate. The solvent is evaporated and the residue is recrystallisedfrom a 1:1 mixture by volume of ethyl acetate and petroleum ether. 155 g(70% of theory) of N-(4-hydroxycyclohexyl)-dimethylmaleimide areobtained; melting point 109° to 111° C.

(b) 4-Dimethylmaleimidylbenzene-1-carboxylic acid

According to instruction a, using p-aminobenzoic acid in place ofaminocyclohexanol.

(c) 4-Dimethylmaleimidylbenzene-1-carboxylic acid chloride

This compound is manufactured in the customary manner from thecarboxylic acid obtainable according to b, using thionyl chloride.

(d) α-Dimethylmaleimidyl-hydroxyalkanes

Some of these compounds (the hydroxyethyl compound and the3-hydroxypropyl compound) are known and the other compounds can bemanufactured in the same way as the known compounds; this applies, forexample, in the case of the 6-hydroxyhexyl compound, the2-methyl-2-hydroxyethyl compound and maleimidylalkanols which have afused ring, such as ##STR24##

(e) 6-Dimethylmaleimidyl-caproic acid

145 g (1.15 mols) of dimethylmaleic anhydride and 150 g (1.15 mols) ofε-amino-caproic acid are dissolved in 700 ml of anhydrous acetic acidand the solution is boiled under reflux for 8 hours. The acetic acid isthen distilled off in a rotary evaporator. The residue is dissolved in500 ml of diethyl ether and washed once with 100 ml of 1 N NaOH, whilstcooling with ice, and twice with water. After drying over sodiumsulphate and evaporating the diethyl ether, the residue is crystallisedfrom 150 ml of isopropyl ether. 209 g (76% of theory) of6-dimethylmaleimidyl-caproic acid are obtained; melting point 43° to 45°C.

(f) 6-Dimethylmaleimidyl-caproic acid chloride

This compound is obtained from the carboxylic acid obtainable accordingto e, by means of thionyl chloride.

(g) Dimethylmaleimidyl-acetic acid

According to instruction a, using glycocoll in place of aminocaproicacid.

(h) 5-Dimethylmaleimidylbenzene-1,3-dicarboxylic acid

76.5 g (0.34 mol) of disodium 5-amino-isophthalate are dissolved in 200ml of water at 40° to 50° C. in a 1 liter three-necked flask which isprovided with a reflux condenser and a stirrer. 44.2 g (0.35 mol) ofdimethylmaleic anhydride, dissolved in 300 ml of dimethylacetamide, areadded to this solution, whilst stirring. The pale yellowish solution isthen boiled for 30 minutes at 100° C., whilst stirring continuously. Thesolution is then acidified (Congo Blue), at a temperature of 95° to 100°C., with 10% strength hydrochloric acid. The resulting precipitate isfiltered off after the mixture has cooled to room temperature. The crudeproduct is dried in vacuo at 90° C. 68.5 g (70% of theory) of5-dimethylmaleimidyl-isophthalic acid are obtained; melting point above250° C.

(i) 5-Dimethylmaleimidylbenzene-1,3-dicarboxylic acid dichloride

50.9 g (0.176 mol) of N-(dimethylmaleimidyl)-isophthalic acid (see h),together with 500 ml of thionyl chloride, are boiled under reflux, in a1 liter single-necked flask, which is provided with a reflux condenser,until a clear solution has formed. 5 drops of pyridine are added inorder to catalyse the reaction. The reaction mixture is then evaporatedto dryness in a rotary evaporator, an orange-red residue being obtained.

The orange-red residue is then extracted with anhydrous cyclohexane in ahot extractor, the acid chloride being obtained. After cooling to 20°C., the acid chloride which has precipitated out is separated off byfiltration and recrystallised from cyclohexane (20 g of acidchloride/500 ml of cyclohexane).

Yield: 39.3 g (80.2% of theory); melting point 115.5° to 116.5° C.

(j) 5-Dimethylmaleimidylbenzene-1,2,4-tricarboxylic acid

102.05 g (0.4 mol) of 5-nitrotrimellitic acid are suspended in 260 ml ofwater and 48 g (1.2 mols) of sodium hydroxide, dissolved in 240 ml ofwater, are added. The resulting solution is hydrogenated at 42° C. inthe presence of 10 g of a palladium-on-charcoal catalyst containing 5%by weight of Pd. The reaction solution is filtered, the filtrate isconcentrated to a volume of 150 ml and first 75 ml of toluene and then50.44 g (0.4 mol) of dimethylmaleic anhydride are added and the mixtureis boiled under reflux for 10 minutes. The reaction mixture isevaporated to dryness, the residue is dissolved in 500 ml of hot waterand the solution is acidified with 438 ml of 10% strength hydrochloricacid and cooled to 0° to 5° C. and 14 ml of 32% strength hydrochloricacid are added. The precipitate which has separated out is filtered off,rinsed with 50 ml of ice water and dried at 80° C. in a drying cabinet.The yield of 5-dimethylmaleimidyl-trimellitic acid is 111.1 g (83% oftheory).

(k) 5-Dimethylmaleimidylbenzene-1,4-(dicarboxylic acidanhydride)-4-carboxylic acid

140 ml of acetic anhydride are added to 76.64 g (0.23 mol) of thedimethylmaleimidyltrimellitic acid prepared according to the precedinginstruction j and the mixture is heated to the boil. The acid dissolvescompletely within a short time. The solution is evaporated to dryness,the residue is boiled with 180 ml of benzene and the precipitate isfiltered off and dried at 80° C. in a drying cabinet. 51.8 g (71% oftheory) of 5-dimethylmaleimidyl-trimellitic anhydride are obtained;melting point 181° to 185° C.

(l) 5-Dimethylmaleimidylbenzene-1,4-(dicarboxylic acidanhydride)-4-carboxylic acid chloride

50.43 g (0.16 mol) of the 5-dimethylmaleimidyltrimellitic anhydrideprepared according to instruction k are suspended in 320 ml of benzene,17.5 ml (0.24 mol) of thionyl chloride and 0.5 ml ofN,N-dimethylformamide are added and the mixture is heated 90° C., whilststirring. The turbid solution which has formed after boiling for 15minutes is filtered and the filtrate is cooled.5-Dimethylmaleimidyl-trimellitic anhydride-chloride, which hascrystallised out over sodium acetate, is dried at 80° C./0.5 mm Hg.Yield: 29.6 g (55% of theory); melting point 184° to 185° C.

(m) 5-Dimethylmaleimidylbenzene-1,4-(dicarboxylic acidanhydride)-4-carboxylic acid n-dodecyl ester

23.35 g (0.07 mol) of the 5-dimethylmaleimidyl-trimelliticanhydride-chloride prepared according to instruction 1 are dissolved in70 ml of dioxane, 13.04 g (0.07 mol) of lauryl alcohol, dissolved in 25ml of dioxane, are added, whilst stirring, and the mixture is left tostand overnight. The solution is then evaporated.

35 ml of diethyl ether are added to the residue. After stirring forthree hours, 35 ml of cyclohexane are added to the fine crystallinesuspension which has formed and the precipitate is filtered off anddried at 50° C. in a drying cabinet. 24 g (71% of theory) of5-dimethylmaleimidyl-trimellitic anhydride lauryl ester are obtained;melting point 93° C.

(n) 3-Dimethylmaleimidylbenzene-1,2-dicarboxylic acid anhydride

100 g (0.44 mol) of disodium 3-aminophthalate are dissolved in a mixtureof 90 ml of water and 45 ml of toluene by warming slightly. 55.9 g (0.44mol) of dimethylmaleic anhydride are then added to this solution. Themixture is then heated to the reflux temperature and boiled under refluxfor 10 minutes, whilst stirring. After cooling, the mixture is renderedacid to Congo Blue using 10% strength hydrochloric acid. A yellowprecipitate forms and is separated off by filtration and dried in vacuoat 100° C.

Yield (crude product): 102.4 g (80% of theory).

Melting point: 203° C. (recrystallised from water).

102.4 g (0.35 mol) of 3-(N-dimethylmaleimidyl)-phthalic acid are mixedwith 300 ml of acetic anhydride and this mixture is heated to 130° C.under reflux. It is then boiled under reflux for 10 minutes, whilststirring. After cooling, the mixture is evaporated to dryness, 100 ml ofbenzene are then added to the residue and the mixture is againevaporated to dryness. The residue is then recrystallised from 200 ml oftoluene.

(o) N-[6-Methyl-4-oxa-5-oxo-hept-6-enyl]-dimethylmaleimide ##STR25##

183.0 g (1.0 mol) of 3-hydroxypropyl-dimethylmaleimide and 111.3 g (1.1mols) of triethylamine (dried over NaOH) are dissolved in 400 ml ofdiethyl ether (dried over Na) and the solution is cooled to 0° C.

104.5 g (1.0 mol) of methacrylic acid are allowed to run dropwise intothis solution at such a rate that the temperature does not exceed 10° C.

When the reaction has ended, the mixture is stirred until the reactionmixture has warmed up to room temperature. The triethylaminehydrochloride which has precipitated during the reaction is nowseparated from the remaining reaction solution by filtration. The etherextract is washed with slightly acidified water until neutral, driedwith sodium sulphate and then concentrated in vacuo without heating.About 224 g (89.3% of theory) are obtained.

Analogous manufacturing instructions apply for the compounds of thefollowing formulae: ##STR26##

71.0 g (1.0 mol) of acrylamide and 101.25 g of triethylamine, dissolvedin 200 ml of absolute acetone, are initially introduced. 257.5 g (1.0mol) of 6-dimethylmaleimidyl-caproic acid chloride (compare instructionf), dissolved in 400 ml of absolute acetone, are then allowed to run indropwise, whilst cooling with ice/water, at such a rate that thetemperature does not exceed 40° C. When the reaction has ended, themixture is stirred for a further one hour.

The triethylamine hydrochloride which has formed is then separated fromthe remaining reaction solution by filtration. The acetone extract isconcentrated in vacuo without heating. For further working up, theresidue is taken up in 1,000 ml of diethyl ether and washed with 4 times1,000 ml of water. After drying with sodium sulphate, the ether phase isconcentrated in vacuo without heating. 208.0 g (71.2% of theory) areobtained.

(g) N-[1-Aza-3-methyl-2-oxo-but-3-enyl]-dimethylmaleimide ##STR27##

140.0 g (1.0 mol) of N-amino-dimethylmaleimide and 111.3 g (1.1 mols) oftriethylamine (dried over NaOH) are dissolved in 2,500 ml ofdichloromethane and the solution is cooled to 0° C. 104.5 g (1.0 mol) ofmethacrylic acid chloride are allowed to run dropwise into this solutionat such a rate that the temperature does not 10° C. When the reactionhas ended, the mixture is heated to 40° C. and then stirred for one hourat this temperature.

After cooling to room temperature, the reaction solution is washed withwater until neutral. The dichloromethane extrat is dried over magnesiumsulphate and then concentrated to dryness in vacuo, without heating.About 187 g (90% of theory) are obtained.

(r) Phthalic acid derivative ##STR28##

27.1 g (0.1 mol) of 3-methylmaleimidyl-phthalic anhydride and 13 g (0.1mol) of freshly distilled 2-hydroxyethyl methacrylate are dissolved in500 ml of tetrahydrofurane. 0.5 ml of triethylamine and 0.05 g ofhydroquinone are added to this solution. The mixture is now stirred for24 hours at 50° C. and under dry nitrogen. When the reaction has ended,the solvent is evaporated off by means of a rotary evaporator. Theresidual oil is taken up in 500 ml of ether and the ether solution iswashed first with 100 ml of 0.5 N sodium hydroxide solution and thenwith twice 200 ml of water. The ether solution is then evaporated, about39 g (98% of theory) of a pale yellowish, highly viscous oil beingobtained.

Analogous manufacturing instructions apply in the case of the compoundsof the following formulae: ##STR29##

(s) N-Glycidyl-dimethylmaleimide

28 g (0.224 mol) of dimethylmaleimide are suspended in 600 ml oftoluene, the suspension is heated to the boil and any water which may bepresent is distilled off as an azeotrope. 12.5 g (0.224 mol) ofpotassium hydroxide powder are added slowly and the mixture is kept atthe boil for 2 hours, approximately the theoretical amount of water (4.5ml) being collected. After cooling, the mixture is filtered and thepotassium dimethylmaleimide is washed with acetone and dried.

30 g (0.184 mol) of potassium dimethylmaleimide are suspended in 175 g(1.89 mols) of epichlorohydrin. After adding 0.05 g oftetramethylammonium chloride, the mixture is heated, whilst stirring,and boiled under reflux for 18 hours and is then filtered. Afterremoving the unconverted chlorohydrin by distillation under a waterpumpvacuum, about 30 g of a viscous, pale brown liquid which has an epoxidecontent of 4.9 equivalents/kg (calculated: 5.5 equivalents/kg) remain.The NMR spectrum of the product corresponds toN-glycidyl-dimethylmaleimide of the formula ##STR30##

(A) Examples of polymers according to the invention which are formed byhomopolymerisation or copolymerisation of monomers containing reactiveC═C double bonds or which are manufactured using homopolymers orcopolymers of this type as starting materials.

EXAMPLE 1

100 g of a copolymer of methyl vinyl ether and maleic anhydride (GANTREZ119) (anhydride content 0.64 mol, η = 5.76 cP) and 121 g (0.66 mol) ofN-(3-hydroxypropyl)-dimethylmaleimide are dissolved in 400 ml of drytetrahydrofurane. 1 ml of concentrated sulphuric acid is then added. Thereaction mixture is kept at 80° C. for 72 hours, whilst stirring. Thehomogeneous, colourless solution is then poured into 1 liter of ether orhexane. The rubbery precipitate is separated off, washed several timeswith ether and then dried in vacuo at 40° C. The mass can then be groundto a white powder.

Yield: 185 g (72% of theory) of polymer.

The course of the esterification can be followed easily by takingsamples and examining these by IR spectroscopy. (Disappearance of theanhydride bands at wave numbers of 1780 and 1850 cm⁻¹ and appearance ofthe estercarboxylic acid bands at 1710 cm⁻¹).

In addition to Example 1, Table I also contains Examples 2 to 27, inwhich modified polymers are characterised. These polymers are obtainedin the manner described in Example 1 by reacting the polymers in column2 with the maleimide compounds in column 3. Column 4 gives the viscosityη in centipoise, measured at 20° C. in an Ostwald viscometer, for a 2%strength solution in cyclohexanone.

                                      Table I                                     __________________________________________________________________________                             Maleimide compound                                    Ex- ample No.                                                                     Polymeric starting material                                                                        ##STR31##         η                             __________________________________________________________________________     1*)                                                                               ##STR32##                                                                                          ##STR33##        12                                  2  as Example 1         "                                                     3  as Example 1                                                                                        ##STR34##        7                                   4  as Example 1                                                                                        ##STR35##        12                                  5*)                                                                              as Example 1         "                                                     6  as Example 1                                                                                        ##STR36##        12                                   7*)                                                                             as Example 1         "                 6                                   8  as Example 1                                                                                        ##STR37##        10                                  9  as Example 1                                                                                        ##STR38##        14                                 10  as Example 1                                                                                        ##STR39##        16                                 11  as Example 1                                                                                        ##STR40##        12                                 12  as Example 1                                                                                        ##STR41##        12                                 13  GANTREZ 139, η = 14                                                                             ##STR42##        32                                 14  as Example 13                                                                                       ##STR43##        30                                 15  as Example 13                                                                                       ##STR44##        31                                 16  as Example 13                                                                                       ##STR45##        32                                 17                                                                                 ##STR46##                                                                                          ##STR47##        7                                  18  as Example 17                                                                                       ##STR48##        7                                  19  as Example 17                                                                                       ##STR49##        7                                  20  EMA 21                                                                                              ##STR50##        18                                 21  as Example 20                                                                                       ##STR51##        20                                 22  as Example 20                                                                                       ##STR52##        18                                 23                                                                                 ##STR53##                                                                                          ##STR54##        30                                 24                                                                                 ##STR55##                                                                                          ##STR56##        15                                 25  as Example 24                                                                                       ##STR57##        16                                 26                                                                                 ##STR58##                                                                                          ##STR59##        20                                 27                                                                                 ##STR60##                                                                                          ##STR61##        20                                 28                                                                                 ##STR62##                                                                                          ##STR63##        28                                 __________________________________________________________________________     *) In the case of the reaction products of Examples 2, 3, 4, 6 and 8 to       28, the half-ester is formed to the extent of 60 to 80% and in the case o     the products of Examples 1, 5 and 7 it is formed to the extent of about 2     to 30%, based on the anhydride groups.    .sup.×) In the case of th     reaction products of Examples 2, 3, 4, 6 and 8 to 28, the half-ester is     formed to the extent of 60 to 80% and in the case of the products of     Examples 1, 5 and 7 it is formed to the extent of about 20 to 30%, based     on the anhydride groups.

The products of Examples 11 and 12 were prepared by the followingmethods.

EXAMPLE 11

7.8 g of GANTREZ 119 and 11.5 g ofN-3-hydroxypropyl-3-methyl-cyclohex-1-ene-1,2-dicarboxylic acid imideare dissolved in 50 ml of dry tetrahydrofurane. The reaction mixture iskept at 80° C. for 7 hours, whilst stirring. After cooling, the clearsolution is poured into 50 ccs of hexane, whilst stirring vigorously.The product, which is isolated by filtration, is dried and thenpowdered.

Yield: 13 g (67% of theory)

EXAMPLE 12

The conditions were the same as for No. 11; quantities: 14. g of GANTREZ119 and 19.5 g of N-3-hydroxypropyl-cyclohex-1-ene-1,2-dicarboxylic acidimide dissolved in 100 ml of tetrahydrofurane. The product wasprecipitated with 200 ml of hexane.

Yield: 21.4 g (64% of theory).

EXAMPLE 29

1 g of a polyvinyl alcohol (MOVIOL 4-98) (0.0227 mol of HO groups) isdissolved, at 140 to 150° C., in 10 ml of dry dimethylformamide. 6.15 gof o-dimethylmaleimidylphthalic anhydride of the formula ##STR64##dissolved in 5 ml of dimethylformamide and 0.1 ml of dry pyridine, arethen added. After the mixture has been treated for 24 hours at 140° to150° C., it is cooled and 50 ml of ether are added and the resultingwhite, rubbery precipitate is separated off, rinsed with ether anddried. 7 g (100% of theory) of the reaction product are obtained.

Dry N-methylpyrrolidone is also a very advantageous solvent for thisreaction. The degree of esterification can be adjusted easily by meansof the quantity of anhydride which is added, so that, for example, 100%esterification or only 20% esterification takes place.

EXAMPLE 34

0.6 g of polyvinyl alcohol is dissolved in 20 ml of drydimethylformamide at 140° C. 20 mg of 1,4-diazabicyclo[2.2.2]octane and1 g of dry triethylamine are then added. 1.5 g of6-dimethylmaleimidyl-caproic acid chloride in 5 ml of drydimethylformamide are added slowly to this homogeneous solution and thereaction mixture is kept at 80° C. for 6 hours. After cooling, thetriethylammonium chloride which has formed is filtered off and thepolymer is precipitated with ether. After drying, 1 g of a whitesubstance ramains. Dry N-methylpyrrolidone can also be used as thereaction medium.

                                      TABLE II                                    __________________________________________________________________________                     Maleimide compound                                            No.Ex.                                                                           materialPolymeric starting                                                                  ##STR65##                                                   __________________________________________________________________________    29 Polyvinyl alcohol MOVIOL 4-98 (Hoechst)                                                      ##STR66##                                                   30*                                                                              as Example 29   "                                                          31 Polyvinyl alcohol MOVIOL                                                                    as Examples 29 and 30                                           20-98                                                                      32 Polyvinyl alcohol MOVIOL                                                                    as Examples 29 and 30                                           4-88                                                                       33 as Examples 29 and 30                                                                        ##STR67##                                                   34 as Example 32                                                                                ##STR68##                                                   35 as Examples 29 and 30                                                                        ##STR69##                                                   36 as Examples 29 and 30                                                                        ##STR70##                                                   __________________________________________________________________________

in the case of the reaction products of Examples 20 and 31 to 36, thehalf-ester is formed to the extent of 100% but in the case of Example30, it is formed to the extent of only about 20%, based on the hydroxylgroup.

EXAMPLE 37

40 g (0.16 mol) of the dimethylmaleimidyl derivative Z I (manufacturinginstructions o), together with 0.1 g of α,β'-azo-bis-isobutyronitrile(azoisobutyronitrile), are dissolved in 260 ml of tetrahydrofuran. Thismixture is polymerised for 6 hours under continuous gentle reflux (about80° C.), whilst stirring and continuously under a nitrogen atmosphere.When the reaction has ended, the mixture is cooled to room temperatureand the polymer is precipitated by adding the reaction solution dropwiseto 5 liters of hexane. 32 g (80% of theory) of polymer are obtained as awhite powder.

H¹ NMR [chlorobenzene, TMS as the internal standard = 0]: 1.96 ppm (6H),methyl protons of the dimethylmaleimide radical.

ηinherent: 0.18 (measured in dimethylformamide at 20° C. in a 0.5%strength solution).

EXAMPLE 38

30 g (0.12 mol) of the dimethylmaleimidyl derivative Z I, together with20 g (0.23 mol) of vinyl acetate and 0.4 g of azoisobutyronitrile aredissolved in 500 ml of ethyl acetate. This mixture is polymerised for 4hours at 70° C., whilst stirring and continuously under a nitrogenatmosphere. When the reaction has ended, the mixture is cooled to roomtemperature and the polymer is precipitated by adding the reactionsolution dropwise to 6 liters of hexane. 42 g (84% of theory) of polymerare obtained.

NMR: 1.98; η: 0.08.

EXAMPLE 39

30 g (0.12 mol) of the dimethylmaleimidyl derivative Z I, together with55 g (0.55 mol) of methacrylic acid methyl ester, 15 g (0.15 mol) ofacrylic acid ethyl ester and 0.4 g of azoisobutyronitrile, are dissolvedin 500 ml of toluene. This mixture is polymerised for 8 hours at 70° C.,whilst stirring and continuously under a nitrogen atmosphere. When thereaction has ended, the mixture is cooled to room temperature and thepolymer is precipitated by adding the reaction solution dropwise to 6liters of hexane. 85 g (85% of theory) of polymer are obtained.

NMR: 1.96; η: 0.18.

EXAMPLE 40

40 g (0.15 mol) of the dimethylmaleimidyl derivative Z II (manufacturinginstructions o), together with 0.3 g of azoisobutyronitrile, aredissolved in 260 ml of tetrahydrofurane. This mixture is polymerised for5 hours under continuous gentle reflux (about 80° C.), whilst stirringand continuously under a nitrogen atmosphere. When the reaction hasended, the mixture is cooled to room temperature and the polymer isprecipitated by adding the reaction solution dropwise to 5 liters ofhexane. 29 g (72% of theory) of polymer are obtained.

NMR: 1.96; η0.18.

EXAMPLE 41

102.75 g (0.40 mol) of the dimethylmaleimidyl derivative Z II, togetherwith 75 g (0.75 mol) of methacrylic acid methyl ester and 0.85 g ofazoisobutyronitrile, are dissolved in 800 ml of tetrahydrofurane. Thismixture is polymerised for 6 hours under continuous gentle reflux (about80° C.), whilst stirring and continuously under a nitrogen atmosphere.When the reaction has ended, the mixture is cooled to room temperatureand the polymer is precipitated by adding the reaction solution dropwiseto 8 liters of hexane. 124 g (70% of theory) of polymer are obtained.

NMR: 1.96; η: 0.05

EXAMPLE 42

100 g (0.39 mol) of the dimethylmaleimidyl derivative Z II, togetherwith 30 g (0.21 mol) of methacrylic acid glycidyl ester, 10 g (0.07 mol)of methacrylic acid 2-hydroxyethyl ester, 10 g (0.05 mol) of acrylicacid 2-ethylhexyl ester and 1.5 g of benzoyl peroxide, are dissolved in850 ml of tetrahydrofurane. This mixture is polymerised for 3 hoursunder continuous gentle reflux. When the reaction has ended, the mixtureis cooled to room temperature and the polymer is precipitated by addingthe reaction solution dropwise to 6 liters of hexane. 113 g (75% oftheory) of polymer are obtained.

NMR: 1.98; η: 0.17.

EXAMPLE 43

20 g (0.07 mol) of the dimethylmaleimidyl derivative Z II, together with10 g (0.09 mol) of 4-vinylpyridine and 0.3 g of azoisobutyronitrile, aredissolved in 250 ml of tetrahydrofurane. This mixture is polymerised for3 hours under continuous gentle reflux (about 80° C.), whilst stirringand continuously under a nitrogen atmosphere. When the reaction hasended, the mixture is cooled to room temperature and the polymer isprecipitated by adding the reaction solution dropwise to 2 liters ofhexane. 24.9 g (83% of theory) of polymer are obtained.

NMR: 1.94; η: 0.14.

EXAMPLE 44

70 g (0.27 mol) of the dimethylmaleimidyl derivative Z II, together with11 g (0.11 mol) of methacrylic acid methyl ester, 14 g (0.16 mol) ofacrylic acid ethyl ester, 5 g (0.03 mol) of methacrylic acid2-hydroxyethyl ester and 0.4 g of azoisobutyronitrile, are dissolved in500 ml of dimethylformamide. This mixture is polymerised for 10 hours at75° C., whilst stirring and continuously under a nitrogen atmosphere.When the reaction has ended, the mixture is cooled to room temperatureand the polymer is precipitated by adding the reaction solution dropwiseto 5 liters of water. 78 g (78% of theory) of polymer are obtained.

NMR: 1.96; η: 0.15.

EXAMPLE 45

70 g (0.27 mol) of the dimethylmaleimidyl derivative Z II, together with25 g (0.29 mol) of acrylic acid ethyl ester, 5 g (0.03 mol) ofmethyacrylic acid 2-hydroxyethyl ester and 1 g of benzoyl peroxide, aredissolved in 500 ml of tetrahydrofurane. This mixture is polymerised for5 hours under gentle reflux (about 80° C.), whilst stirring andcontinuously under a nitrogen atmosphere. When the reaction has ended,the mixture is cooled to room temperature and the polymer isprecipitated by adding the reaction solution dropwise to 4 liters ofhexane. 67 g (67% of theory) of polymer are obtained.

NMR: 1.96 η: 0.20.

EXAMPLE 46

25 g (0.1 mol) of the dimethylmaleimidyl derivative Z III (manufacturinginstructions o), together with 0.2 g of azoisobutyronitrile, aredissolved in 250 ml of tetrahydrofurane. This mixture is polymerised for5 hours under gentle reflux (about 80° C.), whilst stirring andcontinuously under a nitrogen atmosphere. When the reaction has ended,the mixture is cooled to room temperature and the polymer isprecipitated by adding the reaction solution dropwise to 2 liters ofhexane. 18 g (72% of theory) of polymer are obtained.

NMR: 1.98 ppm; η0.08.

EXAMPLE 47

71.5 g (0.24 mol) of the dimethylmaleimidyl derivative Z IV(manufacturing instructions o), together with 0.6 g ofazoisobutyronitrile, are dissolved in 460 ml of tetrahydrofurane. Thismixture is polymerised for 5 hours under gentle reflux (about 80° C.),whilst stirring and continuously under a nitrogen atmosphere. When thereaction has ended, the mixture is cooled to room temperature and thepolymer is precipitated by adding the reaction solution dropwise to 5liters of hexane. 61 g (85% of theory) of polymer are obtained.

NMR: 1.92 η: 0.21.

EXAMPLE 48

20 g (0.07 mol) of the dimethylmaleimidyl derivative Z V (manufacturinginstructions o), together with 27.5 g (0.27 mol) of methacrylic acidmethyl ester, 2.5 g (0.01 mol) of methacrylic acid 2-hydroxyethyl esterand 0.8 g of azoisobutyronitrile, are dissolved in 400 ml of toluene.This mixture is polymerised for 5 hours at 75° C., whilst stirring andcontinuously under a nitrogen atmosphere. When the reaction has ended,the mixture is cooled to room temperature and the polymer isprecipitated by adding the reaction solution dropwise to 4 liters ofhexane. 36 g (72% of theory) of polymer are obtained.

NMR: 1.95; η: 0.11.

EXAMPLE 49

137.4 g (0.34 mol) of the dimethylmaleimidyl derivative Z VI(manufacturing instructions r), together with 0.8 g ofazoisobutyronitrile, are dissolved in 625 ml of tetrahydrofurane. Thismixture is polymerised for 5 hours under gentle reflux (about 80° C.),whilst stirring and continuously under a nitrogen atmosphere. When thereaction has ended, the mixture is cooled to room temperature and thepolymer is precipitated by adding the reaction solution dropwise to 5liters of hexane. 120.7 g (88% of theory) of polymer are obtained. Seethe table for the chemical and physical data.

NMR: 1.96 η: 0.12.

EXAMPLE 50 40.1 g (0.1 mol) of the dimethylmaleimidyl derivative Z VI,together with 30 g (0.3 mol) of methacrylic acid methyl ester, 5.0 g(0.03 mol) of methacrylic acid 2-hydroxyethyl ester and 0.6 g ofazoisobutyronitrile, are dissolved in 340 ml of tetrahydrofurane. Themixture is polymerised under gentle reflux (about 80°

C.), whilst stirring and continuously under a nitrogen atmosphere. Whenthe reaction has ended, the mixture is cooled to room temperature. 71.9g (95% of theory) of polymer are obtained.

NMR: 1.98; η: 0.14.

EXAMPLE 51

14.4 g (0.02 mol) of the dimethylmaleimidyl derivative Z VII(manufacturing instructions r), together with 20 g (0.2 mol) ofmethacrylic acid methyl ester, 10 g (0.07 mol) of methacrylic acid2-hydroxyethyl ester and 0.4 g of azoisobutyronitrile, are dissolved in270 ml of tetrahydrofurane. This mixture is polymerised under gentlereflux (about 80° C.), whilst stirring and continuously under a nitrogenatmosphere. When the reaction has ended (reaction time about 7 hours),the mixture is cooled to room temperature and the polymer isprecipitated by adding the reaction solution dropwise to 2 liters ofhexane. 27 g (60% of theory) of polymer are obtained.

NMR: 1.94; η: 0.19.

EXAMPLE 52

40 g (0.18 mol) of N-(N-maleimidyl)-dimethylmaleimide of the formula##STR71## together with 18.1 g (0.18 mol) of styrene and 0.23 g ofazoisobutyronitrile, are dissolved in 374 ml of benzene. This mixture ispolymerised for 4 hours under gentle reflux (about 80° C.), whilststirring and continuously under a nitrogen atmosphere. When the reactionhas ended, the mixture is cooled to room temperature and the polymer isprecipitated by adding the reaction solution dropwise to 3 liters ofhexane. 37.2 (77% of theory) of polymer are obtained.

NMR: 1.98 ppm; η: 0.72.

EXAMPLE 53

16.2 g (0.07 mol) of the dimethylmaleimidyl derivative Z IX(manufacturing instructions q), together with 30 g (0.3 mol) ofmethacrylic acid methyl ester and 0.4 g of azoisobutyronitrile, aredissolved in 270 ml of tetrahydrofurane. This mixture is polymerised forabout 6 hours under gentle reflux (about 80° C.), whilst stirring andcontinuously under a nitrogen atmosphere. When the reaction has ended,the mixture is cooled to room temperature and the polymer isprecipitated by adding the reaction solution dropwise to 2 liters ofhexane. 32 g (69% of theory) of polymer are obtained.

NMR: 1.97; η: 0.05.

EXAMPLE 54

13 g (0.1 mol) of the dimethylmaleimidyl derivative of the formula##STR72## together with 26 g (0.26 mol) of methacrylic acid methyl esterand 0.2 g of azoisobutyronitrile, are dissolved in 390 ml oftetrahydrofurane. This mixture is polymerised for 6 hours under gentlereflux (about 80° C.), whilst stirring and continuously under a nitrogenatmosphere. When the reaction has ended, the mixture is cooled to roomtemperature and the polymer is precipitated by adding the reactionsolution dropwise to 4 liters of hexane. 30 g (76% of theory) of polymerare obtained.

NMR: 1.94; η: 0.31.

EXAMPLE 55

6.0 g (19 mmols) of the maleimidyl derivative Z XI (manufacturinginstructions o), together with 0.06 g of azoisobutyronitrile, aredissolved in 40 ml of tetrahydrofurane. This mixture is polymerised for4 hours under gentle reflux, whilst stirring and continuously under anitrogen atmosphere. When the reaction has ended, the mixture is cooledto room temperature and the polymer is precipitated by adding thereaction solution dropwise to 500 ml of hexane.

5.8 g (96% of theory) of polymer are obtained.

NMR: η: 0.18

EXAMPLE 56

100 g (0.24 mol) of the dimethylmaleimidyl derivative Z VI(manufacturing instructions r), together with 2.2 g of dodecylmercaptanand 1.8 of azoisobutyronitrile, are dissolved in 200 g (2 mols) ofmethacrylic acid methyl ester.

This solution is suspended in a mixture of 600 ml of water and 1.8 g ofMOWIOL N-88 (polyvinyl alcohol). This suspension is polymerised for 6hours at 70° C., whilst stirring and continuously under a nitrogenatmosphere. When the reaction has ended, the mixture is cooled to roomtemperature and the resulting polymer (in the form of fine beads) isseparated off by means of filtration. The polymer is washed severaltimes with water and then dried in vacuo at 40° C. 233 g (77% of theory)of polymer are obtained.

EXAMPLE 57

142.2 g (0.06 mol) ofN-[5-methyl-3-oxa-4-oxo-hex-5-enyl]dimethylmaleimide (ZI), 36.8 g (0.2mol) of acrylic acid 2-ethylhexyl ester, 34.2 g (0.2 mol) of acrylicacid diethylaminoethyl ester, 2.13 g (1% by weight, based on the weightof monomer) of azoisobutyronitrile and 518 ml of glycol monoethylether-acetate are initially introduced, under a nitrogen atmosphere,into a reaction vessel in which the temperature can be controlled bymeans of a thermostat.

The mixture was then heated to 80° C. and stirred at this temperaturefor about 8 hours. (Stirring speed = 250 revolutions/minute). Aftercooling, it was possible, after adding the desired sensitiser, to usethe resulting polymer solution direct in order to producephoto-sensitive layers.

EXAMPLE 58

189.5 g (0.8 mol) ofN-[5-methyl-3-oxa-4-oxo-hex-5-enyl]-dimethylmaleimide, 34.2 g (0.2 mol)of acrylic acid diethylaminoethyl ester, 2.24 g (1% by weight, based onthe weight of monomer) of azoisobutyronitrile and 700 ml of glycolmonoethyl ether-acetate were initially introduced, under a nitrogenatmosphere, into a reaction vessel in which the temperature can becontrolled by means of a thermostat.

The mixture was then heated to 80° C. and stirred at this temperaturefor about 8 hours (stirring speed = 250 revolutions/minute).

After cooling, it was possible, after adding the desired sensitiser, touse the resulting polymer solution direct in order to producephoto-sensitive layers.

EXAMPLE 59

118.5 g (0.5 mol) ofN-[5-methyl-3-oxa-4-oxo-hex-5-enyl]-dimethylmaleimide (ZI), 30.0 g (0.3mol) of acrylic acid ethyl ester, 20.0 g (0.2 mol) of methacrylic acidmethyl ester, 1.68 g (1% by weight, based on the weight of monomer) ofazoisobutyronitrile and 525 ml of glycol monoethyl ether-acetate wereinitially introduced, under a nitrogen atmosphere, into a reactionvessel in which the temperature can be controlled by means of athermostat.

The mixture was then heated to 80° C. and stirred at this temperaturefor about 8 hours (stirring speed = 250 revolutions/minute).

After cooling, it was possible, after adding the desired sensitiser, touse the resulting polymer solution direct in order to producephoto-sensitive layers.

EXAMPLE 60

130.5 g (0.55 mol) ofN-[5-methyl-3-oxa-4-oxo-hex-5-enyl]-dimethylmaleimide (ZI), 21.6 g (0.3mol) of acrylic acid, 15.0 g (0.15 mol) of acrylic acid ester, 1.67 g(1% by weight, based on the weight of monomer) of azoisobutyronitrileand 570 ml of tetrahydrofurane were mixed, under nitrogen, in a reactionvessel in which the temperature can be controlled by means of athermostat.

The mixture was then heated to 80° C. and stirred at this temperature ofabout 8 hours (stirring speed = 250 revolutions/minute).

After cooling to room temperature, the polymer solution was diluted with600 ml of tetrahydrofurane and then added to 1.5 l of hexane in order toprecipiate the polymer.

Yield = 104.5 g = 84.2% of theory.

EXAMPLE 61

78.2 g (0.33 mol) ofN-[5-methyl-3-oxa-4-oxo-hex-5-enyl]-dimethylmaleimide, 61.6 g (0.36 mol)of acrylic acid diethylaminoethyl ester, 21.6 g (0.30 mol) of acrylicacid and 1.61 g (1% by weight, based on the weight of monomer) ofazoisobutyronitrile are dissolved, under nitrogen, in 734 ml oftetrahydrofurane in a reaction vessel in which the temperature can becontrolled by means of a thermostat and the solution is then heated to80° C.

The solution is stirred for 8 hours under these conditions (stirringspeed = 250 revolutions/minute).

After cooling, the resulting polymer solution is added to 1.5 l ofhexane in order to precipitate the polymer. After filtering, theprecipitate was dried in vacuo at 40° C.

Yield: 85.1 g = 50% of theory; ηinherent = 0.25.

The polymer is soluble in water.

EXAMPLE 62

78.2 g (0.33 mol) ofN-[5-methyl-3-oxa-4-oxo-hex-5-enyl]-dimethylmaleimide, 36.6 g (0.33 mol)of vinylpyrrolidone, 23.8 g (0.33 mol) of acrylic acid and 1.30 g (1% byweight, based on the weight of monomer) of azoisobutyronitrile aredissolved, under nitrogen, in 734 ml of tetrahydrofurane in a reactionvessel in which the temperature can be controlled by means of athermostat and the solution is then heated to 80° C.

The solution is stirred for 8 hours under these conditions (stirringspeed = 250 revolutions/minute).

After cooling, the resulting polymer solution is added to 1.5 l ofhexane in order to precipitate the polymer. After filtering, theprecipitate is dried in vacuo at 40° C.

Yield: 94.2 g = 72.5% of theory, ηinherent = 0.22.

The polymer is soluble in a 5% strength aqueous solution of sodiumbicarbonate.

EXAMPLE 63

A mixture of 6.18 g of a styrene/glycidyl methacrylate copolymer whichhas an epoxide content of 4.0 equivalents per kg and an averagemolecular weight of 3,100, 6.09 g ofN-(p-carboxyphenyl)-dimethylmaleimide (manufacturing instructions b),0.02 g of hydroquinone, 0.03 g of tetramethylammonium chloride and 24 gof cyclohexanone is kept at 120°C. for 13/4hours, after which theepoxide content (based on the solids content of the solution) is still0.3 equivalent/kg.

EXAMPLE 64

A mixture of 4.8 g of the copolymer mentioned at the start of Example63, 3.5 g of N-(carboxymethyl)-dimethylmaleimide, 0.01 g ofhydroquinone, 0.03 g of tetramethylammonium chloride and 15 g ofcyclohexanone is kept at 120° C. for 25 minutes and during this periodthe epoxide content falls to 0.14 equivalent/kg.

EXAMPLE 65

A mixture of 5 g of a styrene/maleic anhydride copolymer (styrene toanhydride ratio equals 1:1, average molecular weight 1,600), 6.5 g ofN-(3-hydroxypropyl)-dimethylmaleimide, 0.02 g of N-benzyl-dimethylamine,0.02 g of hydroquinone and 20 g of cyclohexanone is kept at 120° C. for5 hours. After this period it is no longer possible to detect anysignificant amount of anhydride when the infrared spectrum is examined.

EXAMPLE 66

2.2 g of a polyvinyl alcohol which has an average molecular weight of14,000 and a residual acetate content of less than 3% (GELVATOL 1-30from the Monsanto Company) are dissolved in 40 ml of pyridine bystirring at 50° C. for 3 hours. After adding 9 g ofp-(dimethylmaleimido)benzoyl chloride, the mixture is stirred for afurther 3 hours, then cooled and poured into 150 ml of water and theprecipitate which is thus formed is filtered off. This residue isdissolved in 20 ml of cyclohexane.

EXAMPLE 67

A mixture of 4.26 g of the styrene/glycidyl methacrylate copolymer ofthe composition indicated in Example 63, 3.0 g ofN-(3-hydroxypropyl)-dimethylmaleimide and 15 g of cyclohexanone isstirred at 120° C. for 31/2hours, during which time the epoxide contentfalls to 1.0 equivalent/kg.

(B) Examples of polymers according to the invention of the polyamide andpolyamide-imide type

EXAMPLE 68

Preparation of a 90:10 acid chloride mixture: 40.20 g of isophthaloylchloride and 7.17 g of 5-dimethylmaleimidoisophthaloyl chloride(manufacturing instructions i) are melted together at 70° C., the meltis allowed to solidify and the solid is crumbled.

Condensation reaction: 21.47 g of m-phenylenediamine are dissolved in190 ml of dimethylacetamide, the solution is cooled to -25° C. and 43.07g of the 90:10 acid chloride mixture in the solid form are added all atonce, whilst stirring well and blanketing with an inert gas, and thetemperature then rises to about +30° C. The cooling bath is removed andthe reaction product is stirred for 3 hours at room temperature. Afterdiluting with dimethylacetamide (190 ml), the polymer is precipitatedwith water, whilst stirring vigorously, washed with water until neutraland dried overnight in a vacuum drying cabinet at 120° C. A fibrous,almost white polymer which has a viscosity ηintrinsic = 0.7 dl/g (0.5%weight/volume in dimethylacetamide), is soluble in dimethylformamide ordimethylacetamide without the addition of a salt and can be processed togive films, which after irradiation with UV light are insoluble andtherefore crosslinked, is obtained in quantitative yield.

EXAMPLE 69

70:30 acid chloride mixture: the acid chloride mixture is prepared, inthe manner described in Example 68, from 31.27 g of isophthaloylchloride and 21.53 g of 5-dimethylmaleimidoisophthaloyl chloride.

A polymer which has an intrinsic viscosity of 0.6 dl/g (0.5% strength indimethylacetamide) is prepared, by the process of Example 68, from 21.47g of m-phenylenediamine in 190 ml of dimethylacetamide and 48.00 g ofthe 70:30 acid chloride mixture. Clear transparent films, which can becrosslinked photochemically, are formed from the solution indimethylacetamide.

EXAMPLE 70

19.69 g (0.0993 mol) of diaminodiphenylmethane are dissolved in 150 mlof dry dimethylacetamide and the solution is cooled to -20° C. undernitrogen. 16.74 g (0.07 mol) of sebacic acid dichloride are allowed torun in dropwise at a temperature of -10° to -20° C., whilst stirring,and 9.78 g (0.03 mol) of 5-dimethylmaleimido-isophthaloyl chloride arethen added all at once. The cooling bath is removed and the mixture isstirred for 3 hours at room temperature. The highly viscous yellowishreaction product is precipitated in water, whilst stirring intensively,washed until neutral and dried in vacuo at 80° C. for 24 hours. Ayellowish fibrous polymer which has an intrinsic viscosity η_(intrinsic)of 0.81 dl/g (0.5% strength in concentrated sulphuric acid), is solublein dimethylacetamide plus 5% of lithium chloride and gives transparentfilms, is obtained in quantitative yield.

EXAMPLE 71

34.20 g (0.298 mol) of trans-2,5-dimethylpiperazine and 84.0 ml oftriethylamine are dissolved in 500 ml of dry chloroform. A solution of50.25 g (0.210 mol) of sebacic acid dichloride and 29.35 g (0.090 mol)of 5-dimethylmaleimido-isophthaloyl chloride in 400 ml of chloroform isallowed to run dropwise into this solution at a temperature of -5° C.,whilst stirring. The dropping funnel rinsed out with 100 ml ofchloroform and the reaction mixture is stirred for 1 hour at roomtemperature without a cooling bath. The viscous solution is precipitatedin 2,500 ml of petroleum ether and the fibrous polymer is freed fromtriethylammonium chloride by washing several times with warm water anddried in vacuo at 80° C. for 24 hours. A colourless polymeric productwhich has an intrinsic viscosity η_(intrinsic) of 1.37 dl/g (0.5%strength in concentrated sulphuric acid), is soluble in chlorinatedhydrocarbons, such as chloroform, methylene chloride and1,2-dichloroethane, and forms tough transparent films, is obtained inquantitative yield.

EXAMPLE 72

38.446 g (0.192 mol) of 4,4'-diamino-diphenyl ether are dissolved in 200ml of absolute N,N-dimethylacetamide under nitrogen in a stirredapparatus. The solution is cooled to -15° C. and an intimate mixture of15.0 g (0.048 mol) of 5-dimethylmaleimidylbenzene-1,2-(carboxylic acidanhydride)-4-carboxylic acid chloride and 30.322 g (0.144 mol) ofbenzene-1,2-(dicarboxylic acid anhydride)-4-carboxylic acid chloride issprinkled in, whilst stirring vigorously, at -15° C. to -5° C. Aslightly exothermic reaction takes place and a viscous solution formsand is diluted with 100 ml of N,N-dimethylacetamide and gradually warmedto room temperature. Any insoluble constituents which may be present gointo solution. After stirring for 2 hours at room temperature a further100 ml of N,N-dimethylacetamide are added and the hydrochloric acidformed during the reaction is precipitated with 19.42 g (0.192 mol) oftriethylamine. The salt which has precipitated out is filtered off. Thepolymer has an intrinsic viscosity η of 0.65 dl/g (0.5% strength clearsolution in N,N-dimethylacetamide at 25° C.).

The solution is suitable, optionally after the addition of 1% ofthioxanthone, for casting films and sheets which can be crosslinkedphotochemically and which are obtained in a known manner by evaporatingthe solvent and cyclising the amide-acids to the imide at elevatedtemperature in vacuo. The uncrosslinked cyclised polymer is soluble inN,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone andconcentrated sulphuric acid.

(C) Examples of polymers according to the invention which are of purepolyester character EXAMPLE 73

97.0 g (0.5 mol) of dimethyl terephthalate, 55.8 g (0.9 mol) of ethyleneglycol and 0.04 g of zinc acetate dihydrate were melted together at 150°C. under nitrogen.

The temperature was now raised to 230° C. in the course of about 3hours, during which time the methanol formed distilled off. After 1 hourat 230° C., the temperature of the melt was raised to 270° C. and, atthe same time, 0.05 g of triphenyl phosphite, 0.05 g of antimonytrioxide and 0.3 g of 2,6-di-tert.-butyl-p-cresol were added.

The pressure was now reduced slowly to 14 mm Hg and the mixture wassubjected to polycondensation under this pressure for 20 minutes. Thepolycondensation reaction was then discontinued by admitting nitrogen tothe system and 11.6 g (0.0263 mol) of dimethylmaleimidoisophthalic aciddiphenyl ester were added. The temperature was then lowered immediatelyto 260° C. and a vacuum of 0.1 mm Hg was applied to the reaction vessel.

The polycondensation reaction was discontinued after 1.5 hours underthese conditions.

EXAMPLE 74

97.0 g (0.5 mol) of dimethyl terephthalate, 55.8 g (0.9 mol) of ethyleneglycol and 0.04 g of zinc acetate dihydrate were melted together at 150°C. under nitrogen.

The temperature was now raised to 230° C. in the course of about 3hours, during which time the methanol formed distilled off. After 1 hourat 230° C., the temperature of the melt was raised to 270° C. and, atthe same time, 0.05 g of triphenyl phosphite, 0.05 g of antimonytrioxide and 0.3 g of 2,6-di-tert.-butyl-p-cresol were added.

The pressure was now slowly lowered to 14 mm Hg and the mixture wassubjected to polycondensation for 10 minutes under this pressure. Thepolycondensation reaction was then discontinued by admitting nitrogen tothe system and 24.5 g (0.0555 mol) of dimethylmaleimidoisophthalic aciddiphenyl ester were added. The temperature was then lowered immediatelyto 260° C. and a vacuum of 0.1 mm Hg was applied to the reaction vessel.

The polycondensation reaction was discontinued after 1.5 hours underthese conditions.

EXAMPLE 75

97.0 g (0.5 mol) of dimethyl terephthalate, 55.8 g (0.9 mol) of ethyleneglycol and 0.04 g of zinc acetate dihydrate were melted together at 150°C. under nitrogen.

The temperature was now raised to 230° C. in the course of about 3hours, during which time the methanol formed distilled off. After 1 hourat 230° C., the temperature of the melt was raised to 270° C. and, atthe same time, 0.05 g of triphenyl phosphite, 0.05 g of antimonytrioxide, 0.3 g of 2,6-di-tert.-butyl-p-cresol and 55.1 g (0.125 mol) ofdimethylmaleimidoisophthalic acid diphenyl ester were added. Thetemperature was now lowered immediately to 260° C. and a vacuum of 0.1mm Hg was applied to the reaction vessel. The polycondensation reactionwas discontinued after 1.5 hours under these conditions.

(D) Examples of polymers, according to the invention, of the polyestertype, which are formed by reacting monomeric compounds containingepoxide groups with monomeric compounds containing carboxyl groups ordicarboxylic acid anhydride groups

EXAMPLE 76

A mixture of 5.0 g of butane-1,4-diol diglycidyl ether, 6.9 g ofN-(3,5-dicarboxyphenyl)-dimethylmaleimide, 0.02 g of hydroquinone, 0.02g of tetramethylammonium chloride and 24 g of cyclohexanone is kept at120° C. for 2 hours. After this time the epoxide content is still about0.4 equivalent/kg.

EXAMPLE 77

A mixture of 2.53 g of 1,3-diglycidyl-5,5'-dimethylhydantoin, 5 g ofN-(p-carboxyphenyl)-dimethylmaleimide, 0.02 g of hydroquinone, 0.02 g oftetramethylammonium chloride and 25 g of cyclohexanone is stirred at120° C. for 11/2 hours, after which the epoxide content is still 0.4equivalent/kg. 3.15 g of benzophenonetetracarboxylic acid dianhydrideare then added and the mixture is stirred at 120° C. for 3 hours. Afterthis time the anhydride content of the solution has fallen to about 10%of the original value, as can be seen from the infrared spectrum.

EXAMPLE 78

A mixture of 5.0 g of N-glycidyldimethylmaleimide, 3.2 g of phthalicanhydride, 0.05 g of N-benzyldimethylamine and 20 g of cyclohexanone isstirred at 120° C. for 4 hours, after which the epoxide content is 0.28equivalent/kg.

EXAMPLE 79

The procedure is as indicated in Example 78, but 2.1 g of succinicanhydride are used in place of phthalic anhydride and the mixture iskept under reflux for only 2 hours. The epoxide content falls to 0.45equivalent/kg.

EXAMPLE 80(a)

A mixture of 2.50 g of N-(3,5-dicarboxyphenyl)-dimethylmaleimide, 2.15 gof 1,3-diglycidyl-5,5-dimethylhydantoin, 0.02 g of dimethylformamide and15 g of 2-ethoxyethanol is stirred at 120° C. for 2 hours, after whichthe epoxide content of the product is still about 0.34 equivalent/kg.

EXAMPLE 80(b)

A mixture of 3 g of N-glycidyl-dimethylmaleimide, 1.7 g ofpentaerythritol tetrakis-(3-mercaptopropionate), 0.05 g oftetramethylammonium chloride and 11 g of cyclohexanone was boiled at120° C. for 2 hours. During this time the epoxide content of the product(relative to the original content of the starting materials) fell to0.35 equivalent per kg. 0.1 g of thioxanthone was added to 4 g of thissolution. After irradiation with UV light and developing incyclohexanone, photo-sensitive plates coated with this solution gavegood relief images.

(E) Examples of polymers, according to the invention, based onphenol-formaldehyde condensates (novolac derivatives)

EXAMPLE 81

A mixture of 10 g of an epoxy-novolac resin (a polyglycidyl ether withan epoxide content of 5.61 equivalents/kg obtained from aphenol-formaldehyde resin with an average molecular weight of 420), 5.45g of N-(carboxymethyl)-dimethylmaleimide, 2.29 g of bisphenol A(di-2,2-(p-hydroxyphenyl)-propane), 0.02 g of hydroquinone, 0.05 g oftetramethylammonium chloride and 16 g of cyclohexanone is kept at 120°C. for 21/4 hours. After this time the mixture contains virtually nofurther epoxide.

EXAMPLE 82

A mixture of 4 g of the epoxy-novolac resin of the composition indicatedin Example 81, 4.58 g of N-(p-carboxyphenyl)-dimethylmaleimide, 0.43 gof bisphenol A, 0.02 g of hydroquinone and 18 g of cyclohexanone is keptat 120° C. for 2 hours. After this time the epoxide content of the solidis still 0.38 equivalent/kg.

(F) Examples of polymers, according to the invention, of thepolyethyleneimine type

EXAMPLE 83

2.8 g of p-(dimethylmaleimido)-benzoyl chloride are added to a solutionof 3.0 g of a polyethyleneimine, which has an average molecular weightof 1,650 to 1,950 and a degree of branching which is determined by aratio of primary to secondary to tertiary nitrogen atoms ofapproximately 1:2:1 (MONTREX PEI-18 from the Dow Chemical Company) in 30ml of cyclohexanone, at room temperature, whilst stirring.

The mixture is stirred for one hour at 120° C. and, after cooling, isfiltered. 0.1 g of benzophenone is added to 3 g of this solution and themixture is tested as indicated in Example 28. After 10 minutes' exposureand developing in cyclohexanone, a good image is obtained.

EXAMPLE 84

A solution of 4 g of p-(dimethylmaleimido)-benzoyl chloride in 35 ml ofcyclohexanone is added to a solution of 3.0 g of a polyethyleneiminewhich has an average molecular weight of 450 to 750 and chain branchingin which the ratio of primary to secondary to tertiary nitrogen atoms isapproximately 1:2:1 (MONTREK PEI-6, Dow Chemical Company) and of 1.54 gof triethylamine in 35 ml of cyclohexanone, whilst stirring, and themixture is stirred for a further hour at 60° C. It is then cooled andfiltered.

(G) Examples of polymers, according to the invention, based onpolyethers (phenoxy resins)

EXAMPLES 85 and 86

10 g of the phenoxy resins PKHC or PKHH (Union Carbide) are dissolved in100 ml of N-methylpyrrolidone (dry). 10 g ofm-dimethylmaleimidyl-phthalic anhydride are added and the homogeneousreaction mixture is kept at 100° C. for 24 hours. The cooled solution isthen poured into 500 ml of ether and the product which has precipitatedout is filtered off. After drying, the product is in the form of a whitemass which can be powdered easily.

Yield: 20 g (100% of theory)

IR: strong band at 1,710 cm⁻¹ (carbonyl and estercarbonyl frequency).

Table III shows the structures involved in Examples 85 to 86.

                                      Table III                                   __________________________________________________________________________                                          Maleimide compound                       No.ampleEx-                                                                       materialPolymeric starting                                                                                      ##STR73##                              __________________________________________________________________________    85                                                                                 ##STR74##                                                                                                       ##STR75##                                  Phenoxy resin                                                                 PKHC (Union Carbide)                                                          Molecular weight <30,000                                                  86                                                                                 ##STR76##                        as Example 85                               Phenoxy resin                                                                 PKHH (Union Carbide)                                                          Molecular weight about 30,000                                             __________________________________________________________________________

In the case of the reaction products of Examples 85 and 86, thehalf-ester is formed to the extent of 100%, based on the hydroxylgroups.

(H) Examples relating to the photochemical use of the polymers accordingto the invention

EXAMPLE I

Benzophenone is added to the polymer solution obtained according toExample 63 in an amount such that the benzophenone content is 10%. Thesolution can be used as follows in order to produce a printed circuit:

A copper-coated laminate is coated with this solution and the solvent isallowed to evaporate so that a film about 10 μ thick remains. This filmis exposed under a negative for 3 minutes using a 500 watt mediumpressure mercury vapour lamp at a distance of 230 mm. The image is thendeveloped by washing out the unpolymerised constituents, by mean of awash with cyclohexanone, from the areas which were not exposed. Theareas in which the copper has been bared are then etched with a solutionwhich contains 60 parts of ferric chloride and 10 parts by weight ofconcentrated hydrochloric acid per 100 parts by weight, whereupon a goodrelief image is formed.

EXAMPLE II

If the solution obtained according to Example 64 is tested as indicatedin Example I and exposure is for 15 minutes and developing is carriedout in an acetone/toluene mixture (1:3 in parts by volume), a good imageis obtained.

EXAMPLE III

A mixture of 0.45 g of benzophenone and 0.45 g of Michler's ketone isadded to 9 g of the solution obtained according to Example 65 and theresulting solution is tested using the method described in Example I.After an exposure of 15 minutes and developing in chloroform/carbontetrachloride (1:2 in parts by volume), good relief images are obtained.

EXAMPLE IV

0.9 g of benzophenone are added to 9 g of the solution obtainedaccording to Example 76 and this mixture is tested as described inExample I. After an exposure of 15 minutes and developing in anacetone/toluene mixture (1:3 in parts by volume), an image is obtained.

EXAMPLE V

0.9 g of benzophenone are also added to 9 g of the solution obtainedaccording to Example 77 and the mixture is tested as described inExample I. A good image is obtained after an exposure of 20 minutes anddeveloping in a 5% strength aqueous solution of disodium hydrogenphosphate.

EXAMPLE VI

0.1 g of thioxanthone is added to 5 g of the solution obtained accordingto Example 78 and the mixture is tested as described in Example I. Afteran exposure of 15 minutes and developing in toluene, a relief image isobtained.

EXAMPLE VII

0.1 g of thioxanthone is added to 4 g of the solution obtained accordingto Example 79 and the procedure is then as in Example VI. An analogousrelief image is obtained.

EXAMPLE VIII

A mixture of 0.45 g of benzophenone and 0.45 g of methyl benzoin etheris added to 9 g of the solution obtained according to Example 81 and thewhole is tested as in Example I. After an exposure of 15 minutes anddeveloping in an acetone/toluene mixture (1:3 in parts by volume), agood relief image is obtained.

EXAMPLE IX

0.1 g of thioxanthone is added to 4 g of the solution obtained accordingto Example 82 and the mixture is tested as in Example I. After anexposure of 15 minutes and developing in an acetone/toluene mixture (1:1in parts by volume), a relief image is obtained.

EXAMPLE X

0.1 g of thioxanthone is added to 4 g of the solution obtained accordingto Example 80 and the mixture is tested as indicated in Example I. Afteran exposure of 15 minutes and subsequent developing in cyclohexanone, arelief image is obtained.

EXAMPLE XI

0.3 g of benzophenone is added to 9 g of the solution obtained accordingto Example 66 and the solution is tested by the method described inExample I. After an exposure of 15 minutes and developing incyclohexanone, an image is obtained.

EXAMPLE XII

In order to carry out the test in accordance with the instructions ofExample I, 0.9 g of benzophenone is added to 9 g of the solutionobtained according to Example 67. After an exposure of 10 minutes anddeveloping in cyclohexanone, good images are obtained.

EXAMPLE XIII

The polymers obtained according to Examples 63, 65 and 76 are tested bythe method of Example I but, in each case, instead of benzophenone 0.1 gof thioxanthone is added to 4 g of the solution. Good relief images areobtained after 1 minute with the polymer of Example 63, after 4 to 15minutes with the polymer of Example 65 and after 7 to 15 minutes withthe polymer of Example 76. Thioxanthone thus displays an increasedactivity.

EXAMPLE XIV

0.3 g of benzophenone and 0.12 g of dicyandiamide are added to 6 g of30% strength solution of the reaction product prepared according toExample 63. A copper-coated laminate is coated with this solution. Afterallowing the solvent to evaporate, a film about 203/4 thick remains. Thefilm is exposed under a negative, and then developed in cyclohexanone,as described in Example I, and a good relief image is obtained on thecopper. If this plate is kept at 180° C. for 2 hours, the polymercoating in the image areas displays very good adhesion to the copper andexcellent resistance to solvents. None of the coating is removed whenthe customary acetone rubbing test is carried out, that is to say afterrubbing twenty times with a pad of cotton wool soaked in acetone.

EXAMPLE XV

The present example relates to the manufacture of printed circuits fromcoated copper sheets. The circuits are manufactured according to theknown manufacturing technique, as is described by Bogenschutz in"Fotolacktechnik" ("Photographic Lacquer Technique") Eugen G.Lenze-Verlag, DT 7968 Saulgau [1975], under the following conditions:

Exposure -- 400 watt high pressure mercury lamp at a distance of 40 cmfrom the vacuum table

Original -- silver image of a circuit on a transparent polyester film

Solvent --(for the polymer and for developing the exposed plate)cyclohexanone (CHE) or 1,1,1-trichloroethane (TE)

Concentration -- 5 to 10% of polymer and 0.5% of thioxanthone in thecoating solution

Coating -- whirler-coating at 3,000 revolutions per minute, then dryingfor 5 minutes at 40 to 50° C.

Developing -- in the solvents mentioned, then drying for 5 minutes at80° to 100° C.

Etching -- in a 60% strength solution of ferric chloride

Copper laminates coated with the polymers of column 1 in Table IV whichfollows are exposed for the time indicated in column 2 and then treatedwith the developer according to column 3.

CHE denotes cyclohexanone and TE denotes 1,1,1-trichloroethane.

                  Table IV                                                        ______________________________________                                        Polymer                  Polymer                                              according                according                                            to Example                                                                            Exposure Devel-  to Example                                                                            Exposure                                                                             Devel-                                No.     (seconds)                                                                              oper    No.     (seconds)                                                                            oper                                  ______________________________________                                        1        5       CHE     86                                                   10      20       CHE     37      40     TE                                    11       5       TE      38      20     TE                                    12       5       CHE     39      40     TE                                    13      10       CHE     40      20     TE                                    18      10       CHE     41      40     TE                                    19      10       CHE     43      40     TE                                    29      60       CHE     44      40     TE                                    31      60       CHE     45      40     TE                                    32      60       CHE     49      40     TE                                    33      60       CHE     51      60     TE                                    85      40       TE      52      40     TE                                    ______________________________________                                    

It is possible to achieve flawless etching using the exposure timesindicated in column 2. All of the polymers crosslinked in the indicatedmanner display a good resistance to solvents. Storage for 24 hours indimethylformamide or cyclohexanone leads to no impairment on etching. Inaddition, the crosslinked polymer on the copper surface is resistant tothe etching solution for 12 to 24 hours.

EXAMPLE XVI

This example relates to images which are produced by photo-crosslinkingof the polymers according to the invention and are rendered more readilyvisible by staining. The exposure is effected using a 400 watt highpressure mercury vapour lamp at a distance of 40 cm from the vacuumtable. A twelve-step wedge with a sixty screen and a one hundred andtwenty screen and a ten-step wedge with density differences of 0.21serve as the original.

Solvent --for the polymer and also for developing the exposed plate:cyclohexanone or a 5% strength aqueous solution of sodium bicarbonate

Coating --by whirler-coating at 2,000 to 3,000 revolutions per minute

Developing --for 30 seconds in sodium bicarbonate solution

The image-wise crosslinked polymer can then be stained easily using acationic dyestuff, for example that of the formula ##STR77## appliedfrom aqueous solution and the image is rendered readily visible by thismeans.

Sensitising -- the triplet energy of the sensitiser must be higher than50 kcals/mol. The concentration of the sensitiser is 1%.

The results obtained with different polymers and sensitisers aresummarised in Table V which follows. CHE denotes cyclohexanone.

                                      Table V                                     __________________________________________________________________________    Polymer                                                 Steps of the          according                                               continuous            to Example                                                                          Dissolved                        Exposed                                                                            Image of the                                                                              wedge shown           No.   in     Sensitiser                seconds                                                                            having screen                                                                             in the                __________________________________________________________________________                                                            image                 1     CHE, 10%                                                                             Thioxanthone               2   complete    5                     2     CHE, 10%                                                                             Thioxanthone              1/2  complete    5                     3     CHE,  5%                                                                             Thioxanthone               1   complete    6                     6     CHE, 10%                                                                             Thioxanthone               2   complete    6                     6     CHE, 10%                                                                             Thioxanthone              10   complete    10                    6     CHE,  5%                                                                             Thioxanthone              10   complete    10                    6     CHE,  5%                                                                             Michler's ketone          10   incomplete  5                     6     CHE,  5%                                                                             Benzophenone              10   incomplete  1                     6     CHE,  5%                                                                             Benzil                    10   incomplete  1                     6     NaHCO.sub.3, 5%                                                                       ##STR78##                10   complete    10                    6     CHE,  5%                                                                             Without sensitiser        10   not readily                                                                               0is-                                                              cernible                          7     CHE, 10%                                                                             Thioxanthone              60   complete    5                     9     CHE, 10%                                                                             Thioxanthone               2   complete    5                     10    CHE, 10%                                                                             Thioxanthone              10   complete    10                    11    CHE,  5%                                                                             Thioxanthone              10   complete    9                     13    CHE, 10%                                                                             Thioxanthone              20   complete    10                    18    CHE, 10%                                                                             Thioxanthone              20   complete    6                     19    CHE, 10%                                                                             Thioxanthone              30   complete    7                     20    CHE, 10%                                                                             Thioxanthone              10   complete    10                    29    Dimethyl-                                                                            Thioxanthone              60   complete    6                           formamide                                                                     5%                                                                      __________________________________________________________________________

If the pre-sensitised plate is developed with organic solvents or if,after developing with a base, an acid bath is used, the aluminium platecan be used as a planographic printing plate.

EXAMPLE XVII

The example relates to processes for producing relief images ontransparent carriers, which images are produced by photo-crosslinking ofthe polymers according to the invention and can be developed in organicsolvents.

A solution consisting of 89 parts by weight of 1,1,1-trichloroethane, 10parts by weight of the polymer of Example No. 45 and 1 part by weight ofthioxanthone is applied, by the casting method, to a polyester film anddried. The photo-sensitive film thus formed has an average layerthickness of 1 to 3 μ and is exposed through a photographic step wedgeto a 400 watt high pressure mercury lamp for 15 to 60 seconds. The imageis then developed in 1,1,1-trichloroethane. The relief image thusobtained shows all 10 steps.

EXAMPLE XVIII

This example relates to processes for producing relief images, which canbe stained, on transparent carriers, which images are produced byphoto-crosslinking of the polymers according to the invention and can befixed, and developed, in pure water.

A thin layer (0.5 to 1.5 μ thick) of gelatine is applied, by the castingmethod, to a polyester carrier which can be used for photographicemulsions and is allowed to crosslink by the action of heat. Thegelatine layer is then coated with an aqueous solution consisting of 89parts by weight of water, 10 parts by weight of the polymer of ExampleNo. 61 and one part by weight of the photosensitiser of the formula##STR79## so that a photo-sensitive layer 0.5 to 3 μ thick is obtained.The dried film is exposed through a photographic wedge with 10 steps toa 400 watt high pressure mercury lamp for 10 to 30 seconds. The image isthen developed in water. The relief image which is thus obtained andwhich shows all 10 steps of the wedge can be rendered visible using anaqueous solution of a cationic dyestuff.

In the same way it is also possible to produce, and to use,photo-sensitive layers with the polymer of Example No. 62, which isemployed as the sodium salt.

EXAMPLE XIX

This example shows the absolute sensitivity of a polymer according tothe invention.

Exposure --HBO 200 watt extremely high pressure mercury vapour lamp(OSRAM) with a narrow band filter for 366 nm, intensity 4.10⁻⁸ Einstein.cm⁻²

Coating --whirler-coated, at 3,000 revolutions per minute, ontopolyester

Polymer -- according to Example 2, 10% strength in cyclohexanone

Sensitiser -- 1% of thioxanthone

Layer thickness -- 0.8 μ

Developing -- immersed briefly in tetrahydrofurane and subsequentlytreated in 5% strength aqueous sodium bicarbonate solution and then in asolution of a cationic azo dyestuff (Astradiamantgrun, Bayer).

A value of S=5.10⁻⁴ J.cm⁻² was determined for the absolute sensitivityS=Energy/cm² until an optical density was reached. A plot of log E/cm²as the abscissa against the optical density as the ordinate is astraight line from the pair of co-ordinates -3.7; 0.25 to the pair ofco-ordinates -2; 4.5 and between the abscissa values of -2 and 1.5 thevalue of the ordinate remains constant at 4.5.

What is claimed is:
 1. A polyether, which can be crosslinked under theaction of electromagnetic waves, having an average molecular weight of1000 to 1,000,000 as measured by viscometry of a solution of 0.2 gram ofpolymer in 100 ml of N,N-dimethylformamide, which is characterized by astructural formula comprising chain members of the formula ##STR80## inwhich MI denotes the maleimido group of formula I ##STR81## wherein Rand R₁ independently of one another denote alkyl of 1 to 4 carbon atoms,or R and R₁ conjointly denote the remaining part of a five-membered tosix-membered carbocyclic ring,Y₃ represents an aliphatic,cycloaliphatic, carbocyclicaromatic, araliphatic, heterocyclic-aliphaticor heterocyclic-aromatic radical containing in each case, a total of atmost up to 18 carbon atoms or denotes the grouping ##STR82## and R₈represents hydrogen, carboxyl or --COO(CH₂)_(z) CH₃ where z is 0 to 18.2. A polyether according to claim 1 wherein the maleimido group MI is##STR83##
 3. A polyether according to claim 2 wherein the maleimidogroup MI is ##STR84##
 4. A polyether according to claim 1 wherein Y₃ isa carbocyclic-aromatic radical.
 5. A polyether according to claim 4wherein Y₃ is carboxyphenylene.
 6. A polyether according to claim 1wherein R₈ is hydrogen.